DannyM

Hey Padraig. I never drove the auto but my own preference now having owned the manual would be an auto box. I sold my IS250 about 2 years ago for the reasons mentioned above. I had really high expectations for it which I think was ultimately the problem as the longer I owned it the more I disliked it. It's probably the one car I've owned that I never clicked with. My expectations was it would be an improved upon IS200 manual. They are certainly more refined and grown up but I felt the manual option was an afterthought by Lexus. If I was to repeat I'd 100% go auto and ideally SE-L spec and just enjoy it for a daily cruiser to waft around in. I can't weigh in on the E10 impacts as I sold mine before it came into affect. I'd imagine you'd be relatively safe if you've went for something 08 or older that's been in continuous use. I'd be more concerned about something doing minimal mileage that has E10 sitting stagnant in the fuel system pulling in moisture. I'd start with the E10 additive then. The Wynns stuff is great. I use it in my bikes which range from newish fuel injected to old carburetted stuff. They do sit up over the winter with fuel in the tanks and have had no issues to date.

This may also be an option for people looking for an increase in engine noise without spending a fortune. I'd looked into the OEM Fsport intake myself but couldn't justify the price considering it's only purpose is to increase noise. Did a bit of research and from what I found the major difference is between the standard lower airbox which on the Fsport intake has an additional opening and has no ribbing inside the box. I didn't want to just cut a hole in the airbox so I took to SolidWorks and my 3D printer and replicated the Fsport lower airbox design by printing a flange similar to the Fsport design. This cost me nothing as I have all this to hand but could be an option for those who want a neater solution than a cut up airbox and something less costly than a full induction kit if you can get someone to print the flange. Does exactly what I want, increase in engine noise from 3.5-4.5k+ rpm under load and just like factory everywhere else.

Does your diagnostic have data logging/live reading function? DPFs have pressure sensors for pre and post filter pressure. I'd be looking to see if there is a big pressure difference as this would indicate a blockage.

Hi folks, Said I'd make a post here regarding the IS250 MAF sensor. I've owned my 07 IS250 Sport since September last year. I've always found the gear changes quite juttery with lots of rev hang, poor throttle response pulling away, jerky at low speeds in traffic. Read lots of topics from the US mainly on the manual gearbox/drivetrain in these cars and attributed the cars characteristics to the design. A few weeks ago I started getting intermittent faults for rich condition on both banks. Did some troubleshooting and seen fuel trims were sky high trying to lean the mix out. Given it was both banks showing rich, it was safe to say it was a calibration issue with the MAF sensor. I've had cars with faulty MAF sensors before but none had such an impact on the cars running after being replaced. Power delivery is much smoother, gear changes are no longer jerky and there's no juttering pulling away or at low speeds. Hopefully this may be of some help to someone experiencing similar issues. I had the car on diagnostics before the MAF started giving issues and fuel trims were all perfect and no indicator a faulty sensor at all. I'd say if you're IS250 is decent age like mine with a few miles on it, its definitely worth replacing the MAF. I'd never have even thought about it only for it did eventually fault out. Dan.

Taken from the Lexus Warranty and Service booklet.

If you look to the right of the factory intake tube you'll see there's a little plastic chamber connected to it. These are called a Helmholtz resonator. Without going into too much detailed, they're used to improve air intake efficiency by cancelling about pressure waves that travel back up the intake tube when the intake valve closes. They're a simple but very clever device. When these are removed the increase in noise is because these pressure wave pulses now travel back up the full intake tube and are audible. The amplification in noise actually indicates inefficiency. As said above, Lexus/Toyota engineering is excellent and its rare they cut corners on design. Performance and efficiency go hand in hand so it benefits manufacturers to design engines with as much performance as is feasible for design constraints/budget etc.

I have a 2007 on 152k and runs as smooth as it did from day 1, you can easily leave a coin balance on the radiator cap when it's running. They are overall a very solid car. The auto is definitely the one to go for. Having owned the manual one if I was to buy again I'd definitely get the auto. Only issue I had with mine is the alternator. It had previously replaced with a spurious one which died after 6 months, I replaced it with same again which didn't last long either. It's been fitted with a genuine Denso alternator plus a new battery so that should keep it sweet. It's a very well balanced chassis. I have the sport and haven't once thought about modifying the suspension. It's super compliant cruising down the road and confidence inspiring through corners. They're not the lightest car but hide their weight very well. As said, one thats well maintained shouldn't give you any real hassle. I always buy service parts from Toyota as theres very little difference in the price between OEM and spurious (at least here in Ireland anyway). Be picky and hold out for the spec you want and get one with good history and you won't be disappointed!

Did you check the clutch switch to see if the pedal is engaging it when pressed to the floor? Would seem the most likely culprit to me either pedal is not engaging it or switch has failed. Mine is very sensitive in my 250, unless the pedal is hard against the floor it won't start.

Spotted that you used an Exedy clutch kit and wanted to know how you rate it. The clutch was replaced in my 250 just before I bought it 6 months ago (OEM clutch kit was fitted). I'm not a fan of it at all. Pressure plate is quite soft, very difficult to gauge the biting point and clutch is very sensitive (it's very easy slip it on a hill start!). Did you find the Exedy any better or is it much of a muchness being an OEM replacement? Cheers.

Thanks Texas thats great info. I typically do go for OEM parts, all my services I use OEM parts and did price a Denso but given the cost difference I opted for a remanufacture unit. Now though in hindsight I'd rather have forked out for a Denso. If it's known that spurious/reconditioned alternators don't agree with the car I'm happy to pay for a genuine one. Once it's not an issue with the car causing the alternators to blow as at the minute I feel like I can't trust the car. Thanks for forwarding on that thread link. Nice to know someone has had a similar experience and resolved it.

Hi folks, I own a 2007 IS250 sport which I've had since September last year. Car has been meticulously owned by the 2 previous owners and also by myself in my ownership. I was told by the previous owner when I bought the car that there had been some maintenance carried beforehand including an alternator replacement. Car has been faultless up until February when the alternator began to fail. I replaced it with a new/reconditioned unit from a reputable company through my trusted local motor factors. The old alternator I removed was a brand I'd never heard of so put the premature failure down to that. Today my alternator died again. I inspected the wiring when I replaced it in February and again today and nothing appears out of sorts. I'm starting to suspect there is an underlying issue here. Has anybody had a similar experience with alternator failures in their IS250 or am I just so unlucky as to get another dud alternator the last time? There's nothing to indicate there's electrical problems with the car. It's not been modified, everything appears in good condition, battery looks relatively new and holds charge there's never any issue starting after the car has been sat up. Any insight or advice from people whove had similar issues would be much appreciated. Cheers, Dan.

You need to look at your fuel trims with a scan tool to see what the management is doing. I had a rich condition recently with my 250 but on both banks. I knew it was highly unlikely both o2 sensors would fail at once. Diagnostics showed negative short and long term fuel trims on both banks indicating a false MAF reading. I cleaned the MAF and all returned to normal. You need to log the short term fuel trims for both banks and see what's going on. If your fuel trims are positive, the ECU is adding fuel because the o2 sensor sees the mix as lean. On the other hand, if the fuel trims are negative, the o2 sensor sees the mix as rich and is subtracting fuel. If your trims are within +/- 5% on bank 1 then you're o2 sensor is reading correctly. If both banks are showing similar fuel trims then it's more likely a MAF issue. Pre-o2 sensor holes in the exhaust can also create false readings as a venturi effect will draw ambient air into the exhaust flow and tell the sensor it's lean. I'd start with comparing your fuel trims between banks and look for an imbalance. Being you have a lean condition your trims will be positive. If it's good on bank 1 and not on bank 2, focus your attention towards o2 sensor and or a pre sensor exhaust leak. If both banks show negative even if bank 1 hasn't triggered a fault code yet, I'd be looking at the MAF sensor. Hope that helps, Daniel.

+1 for getting an OBD2 scanner plugged in. If it's lit up the dash it will have stored a fault in the ECM. My 250 did the very same for a rich condition fault.

Hi Rustyau, I haven't worked with DET3s before but |I'm well versed in this field so may be able help you. I've pulled the data sheet from the ecumaster website which has the wiring diagrams. Closest thing listed is a Toyota Supra so you'll need an ECU pinout for the IS200. I believe I have the workshop manual for the GXE10 with the wiring schematics, I'll have a look later and get back to you. The DET3 is a piggyback ECU so it manipulates sensor inputs to fool the ECU into giving a different desired output. Your DET3 has 12V switched power plus GND. Your DET3 inputs are crank position signal and MAP signal. Then your output from your DET3 is a modified crank position signal and a MAP signal. Essentially, you'd find the signal wires from the crank position and MAP sensors, cut them and join the sensor side into the corresponding pins on the DET3 then join the Lexus ECU side into the corresponding pins on the DET3. You can trace the wires back from the pins to the ECU if you don't have a pinout diagram to determine what does what in the IS200 ECU. You can use a multimeter to test continuity and identify different circuits. I wouldn't use a test light as sensor signals are 5V not 12V. https://www.ecumaster.com/download/ Danny.

Hi all, Looking for members experiences on e-throttle controllers such as the APEXi SMART Accel. My understanding is they take the voltage signal from the pedal and boost that signal to the throttle position input on the ECU. Has any one any experience with these on the IS250? I only came across 1 or 2 old threads with reference to them. My sole purpose for wanting one would be to increase throttle response and reduce rev hang on gear changes. Cheers, Dan.

The ETCS does do a lot of secondary functions like idle control, traction control etc so I wouldn't be surprised if the Toyota engineers stuck something in there for emissions control. The swap you want to do is the 3 litre v6 from the GS300 which is the 3GR, is that correct? The 2.5 in the IS250 is the 4GR. I've had a couple of BMWs in the past albeit older ones but I will say they don't age well. From the interior they suffer badly from bolster tears in the drivers, seat wear on steering wheels can also cause splitting in the leather. An equivalent age and mileage Lexus won't have those issues. I still love BMWs though they are fantastic drivers cars. The BMWs can be a bit of a minefield regarding engines so you do need to be careful with which you buy and the maintenance. I live in Ireland and we have massive depreciation here on larger petrol engine cars and cars older than 2008 as our motor tax favours newer diesel cars and small engine petrol cars. I actually went onto the way back when web page and looked up the original for sale price of the IS250 here. Mine is a sport with the nav and sunroof and they were €60,305. For the price I paid you're talking €4,300 per year in depreciation. That is the nature of the Irish market here I don't know how the UK market fairs in comparison. The most popular cars here at the min are the likes of Hyundais as the Irish have a "new car mentality" where they prefer having a brand new reg numberplate on low spec cheaper brand cars than buying something a few years older for the same money with nicer spec. All our nice spec cars here tend to be UK imports. My IS250 was originally a Northern Irish car.

I changed the gear oil myself. I personally don't see the need to flush it. If you drain the old oil shortly after a drive when it's still warm you'll get the majority of the old stuff out. I'd recommend ordering up new crush washers from the dealer for the fill and drain plug. They're not expensive, think I paid €0.50 ea and got 4 as I did the diff too. The attached video wouldn't be applicable as that's an auto transmission and they do require a bit more care when doing an oil change. The manual is just a case of fill until oil begins to trickle back out of the fill plug. The car must be level when you do this of course. I'd also recommend you open the fill plug first before the drain as good practice! That way you won't have lost all the oil out of it before you realise you can't refill it. I think the ETCS is the biggest culprit for the rev hang. There's a bit of a delay before it registers you've taken your foot off the accelerator on a gear change. If you've ever driven the XE10 IS200 the ETCS delay can be really noticeable in that. Not so much rev hang but delay in throttle response at certain engine loads. That said the XE10 has gen1 ETCS with cable drive throttle onto a TPS with a stepper motor throttle plate. Lexus' do use dual mass flywheels so the high inertia also contributes to the rev hang. It's taken me a long time to get used to! Would definitely agree that rev match downshift helps massively. I'm a bit sceptical about how much the remaps can change the throttle mapping. You could potentially map it in your favour in that under certain conditions you've less error feedback and it's a bit quicker to reach its target position. You wouldn't have control over the feedback gains though which is ultimately what will drive its ability to respond quickly and accurately to changes in driver input. I'd love to see a 3GR manual swap in one. It's such a shame we didn't get a 350 in Europe. Even the US still got a bit short changed with the only option of an auto 350 too. It's understandable why Toyota didn't offer a manual option though, was never going to be a big seller.

Looks like your valve cover gasket is leaking. If it's never been done before it'd be worth checking your PCV valve and cleaning/replacing it also. If the crankcase is over pressurised the oil vapours will find there way out through various seals and gaskets in the engine. For peace of mind I'd just replace the PCV and valve cover gasket as they're relatively inexpensive and not difficult to change.

Quick update on this for anyone who's interested. Replaced both my differential and gearbox oil 2 weeks ago. Turns out my gearbox was overfilled with oil. It must have been filled from the top previously (if that's possible on these) as at least a litre came out of the fill plug when I opened it! Replaced with Motul Gear 300 and there is a night and day difference. Shifting is much smoother and 5th gear crunch at high rpm is all but cured. Danny.

Thanks Jez. It was done at a Toyota dealer so I'd like to assume it was the correct 75w85/90 GL5 oil. That said I don't know the details of work done as it was before I owned it. I have myself replaced clutches leaving the prop shaft in so they could've done that. I've never actually spoke to anyone whose used a gearbox additive so great to here you've had success with it. I wanted to change it regardless for peace of mind so I will try a synchro additive with it. I tend to do full service and fluid change anytime I buy a car regardless of history. Cheers for your help. Danny.

Hi everyone, New to the forum, not new to the Lexus brand. I've recently purchased a 2007 IS250 manual with 140k miles. Loving the car so far, my own one slight dislike so far being the gearbox. Is there an inherent issue with the synchros in the Aisin RA6 gearbox fitted in the IS250? I've seen a number of complaints for different issues with these gearboxes on US Lexus forums including crunching between gears. For me personally, I find that when I try and shift quickly from 4th to 5th or 5th to 6th gear at high rpm there is a slight crunch. If you don't rush your gear change there is no problem. I've also noticed that there is a rev hang when you clutch in. I believe this is down to the nature of drive by wire throttle and or heavy flywheel. Has anybody here have similar nuisances with the IS250 manual gearbox? Just trying to determine if there are inherent issues with the gearbox or if it's more my driving style I need to adapt. Clutch was just changed on the car before I bought it. Definitely not a make or break problem either way. As a full package I love the car and it's something I can live with. All the best, Danny.