MUDGUTS

...Well it's with a 1UZ-FE specialist now, so far they have discovered a host of fault codes, most seem to have been related to stuff previous techs may have been touching. (When it left garage #1 they assured me it had no fault codes), these have all been cleared but one required the fitting of another O2 sensor. This could have been as the wrong sensor was replaced at garage #1. In any case it hasn't made any difference. Should know more tomorrow.

The suspension is a little bit of a mystery. I called the dealer who originally supplied the vehicle and they don't have info this far back. It has 5 DHP alloys but the bolt isn't long enough to hold the spare down. So that leads me to believe they were fitted after purchase... It certainly is a firm ride though.

His the latest list of things to check / already checked: Exhaust & Catalytic Converters checked Valve timing checked EGR valve cleaned & checked Throttle Body & Plenum Chamber cleaned Distributor Caps, Rotor Arms & HT Leads replaced (Old Spark plugs were not suspect so replaced after new ones tried) Engine sensor connections checked Gearbox shift position sensor (confident this isn't at fault) Fault code 21 cleared with new oxy sensor Throttle position sensor checked MAF Sensor unpugged: Check engine light is on, engine runs rough and won't rev up much Battery off for 30+ mins: Was disconnected at the dealers Air Filter replaced To Check: MAF Sensor ECU A temp sensor Faulty water pressure cap

...I now own one.

If I were to call the original Lexus dealer who supplied the car and quote the the VIN, would they be able to confirm the spec? or is there another way? On the subject of tyres, once the other issues are dealt with I'll be putting new ones on.

This is interesting as the car does ride quite firm but I understand the DHP wasn't offered on the MK 3. My car was first resistered August 1997. DHP was an option on the MK3 ;) Andy Thanks Andy, this explains a lot. The ride is quite firm and I was suprised when I first drove it how un-'barge'-like it was. It must have the DHP.

It's booked in with a 1UZ-FE specialist for the 20th of this month. As bazgtr says, it's most likely to be MAF or ECU related. I have done fairly large (300 Mile) trips recently and apart from this issue it has performed very well, with around 30-32 MPG on these. I'll keep everyone posted.

This is interesting as the car does ride quite firm but I understand the DHP wasn't offered on the MK 3. My car was first resistered August 1997.

Ok just before I go to bed (was up at 0400) here is the latest list of things to check / already checked: Exhaust & Catalytic Converters checked Valve timing checked EGR valve cleaned & checked Throttle Body & Plenum Chamber cleaned Distributor Caps, Rotor Arms & HT Leads replaced (Old Spark plugs were not suspect so replaced after new ones tried) Engine sensor connections checked Gearbox shift position sensor (confident this isn't at fault) Fault code 21 cleared with new oxy sensor Throttle position sensor checked MAF Sensor unpugged: Check engine light is on, engine runs rough and won't rev up much Battery off for 30+ mins: Was disconnected at the dealers Just done a check on fuel consumption after filling up: 75% motorway and the rest in town: 25 MPG To Check: Remove air filter MAF Sensor ECU A temp sensor Faulty water pressure cap

Thanks Baz, I'll check the MAF connector again and wiring as far a I can, I'll have a look at the ECU also. I can have a look at these tomorrow. The D and E I'll try when I'm next off from work. It could be a while before I get a chance. Thanks again.

Ok Gents I have picked the car up today from the Lexus dealer. The following things have been done: Exhaust & Catalytic Converters checked Valve timing checked EGR valve cleaned & checked Throttle Body & Plenum Chamber cleaned Distributor Caps, Rotor Arms & HT Leads replaced (Old Spark plugs were not suspect so replaced after new ones tried) Engine sensor connections checked On the way back I stopped in a layby and tried revving it up: If you build up the revs gently it seems to get to the redline now and blipping the throttle achieves the same but (and here is the symptom that hopefully will enlighten someone): If you floor the throttle the revs immediately drop to 4000 RPM for as long as you hold your foot to the floor. If you then release it the revs will rise right up again. Also if you play about with the throttle the engine sort of surges... Any suggestions welcome

None of this will fix your rev problem MAF meter all the way. Faulty when under load of the throttle. This problem will not show up in any garage which include lexus dealer unless they go out on the road with a laptop inside the car while driving full stop. Just a quick second thought what work if any was carried out before the fault or did it just happen overnight while driving? Also don't scrap, I'll have it with the problem if car is in ok condition. Baz. I bought the car for £884 and it has had the fault since then, the first garage suspected the MAF... But the next one I put on changed nothing.

OK, I'm going to start a list of things to check that may not have been looked at. Before I settle with the Lexus dealer I will obtain a list of exactly what has been checked. To Check: Battery off for 30 mins (can pulling the ECU fuse achieve the same?) Gearbox shift position sensor (don't actually know where this is) Remove air filter MAF Sensor (again), will the car run without it? and is it possible to short wires out to trick it into a false reading? ECU: How easy is this to change? A temp sensor Faulty water pressure cap

Thanks CD, do the above produce fault codes? If so then the top paragraph can be eliminated, the Lexus dealer is sure the timing belt is OK. Pretty sure its not the brakes.

Not 100% sure if this has been checked but it senses enough demand to kickdown when you are moving and the first garage did check the throttle position

Thanks AdeV, It seems to be a fairly fixed limit, apart from the time I blipped it and got 5000, no juddering, ever. It pulls OK to 4000 but when I get it back I can try to offer more info. The fuel filter near the rear had been replaced. I'm not so sure about fuel starvation as I have had it up to quite a speed where it must be using quite a bit of fuel and probably more fuel flow than 4000 at standstill.

The latest is that the Lexus dealer is stumped and can only suggest coking up of the engine, which to clear, would obviously mean more money, which I can't justify. Thanks Guys, I'm going to settle up with the Lexus dealer then bring it home and try as many of the things you have suggested as I can. It's a pity this can't be fixed or at least diagnosed. One of the problems I have is that I have hardly any time at home so tinkering is not really an option but I will try as much as I can.

Plugs, HT Leads, Dis. caps and Rotors all changed and the problem is still there. If I can't get this fixed in the next week, it's going to the scrapyard.

Thanks Guys, at this stage the Lexus dealer has assured me that to replace Plugs, HT Leads, Dis. caps and Rotors is the best course of action. As I said before the lack of a definitive cause is frustrating. The Tech that sat in the car with me thought it was a misfire under load, this may be why it blips to over 5000 but won't hold more than about 4000 whilst on the move.

Hi abs66, no it is around 4000 RPM, 'blipping' the throttle gets a slightly higher RPM like maybe 5000. There is no fixed point that would lead me to believe its an imposed limit, it just won't rev right up. Never tried disconnecting the batt, I should have... Should know more on Monday

Thanks beavisrules, I just don't have the time to get into this myself, so have left it with the Lexus dealer to do. I have asked that they replace the HT leads and plugs first then if that fixes it, I'll make the decision as to whether or not to let them push on and change the Distributor caps. If it does I'm tempted to have them done whilst they are in there and if not, I'll have to let them anyway... Failing this, it looks more expensive. I hope not. I was tempted to get the independant do this but, although the labour rate may be less, they could easily take longer as they won't have the experience. It's a tough call with this as the dealer won't guarantee this will fix the problem... I know its a sound car, it pretty much went straight through the MOT and drives straight, with no suspension issues, no clonking, not issues with the transmission, etc. it's just frustrating to get a car like this and have problems from the beginning.

I though about doing this or trying to reset the ECU. I remember something about ECUs needing to be reset after a new component has been fitted...Have taken it to Lexus MK to see if they can diagnose the problem. The technician sat in it with me and thinks it has a misfire (crap plugs / leads / coil pack). These guys should be able to get to the problem even if I have to replace stuff myself later. This is the problem with cars, you need lots of time to tinker with them, if I had serious time I could have probably tried plugs and tried other stuff. I'm either away with work or on call so dealing with this takes a long time and has to be fitted in. Now I look back I maybe should have taken in straight to the Lexus guys, but then you could be spending lots of money sorting a simple problem. Otherwise it seems to be good...A couple of minor things I can live with or tinker with when I am free. Hi In defence of the Lexus service I can't say that I feel I have paid over the odds for anything they have done on my car in 16 years they will diagnose the problem a lot quicker than anyone else and they will tell you truthfully and precisely what needs doing before they will start any work or replacement of parts. Now if you then resolve to fix the problem somewhere else you have the option,and they don't fall out with you, in fact when I had replacement parts fitted to my LS400 back in 2000 The lexus dealership fitted the parts I had sourced in the USA charging only for the labour but with the proviso there was no guarantee on the parts or subsequent knock on effects to other components. I try to fix the fixable things on my car but inevitably there will come a time that this can only be done in a Lexus workshop and I think in my particular situation that will mean a new Lexus as the values of a 1990 or pennies and any serious engine or transmission fault would spell curtains for this old girl. I think you could have a point there ambermarine. The money I have spent with a local (although reasonable) garage chasing this may have been better spent having Lexus diagnose the fault in the first place. Having said that, they would have also found the duff oxy sensor and I would have had them change this. That would have been more expensive than having an independent do it. ...The latest is that the Lexus dealer can't find the fault and 'suspect' the distributor. To replace this would involve some serious labour. I would be very grateful for any input.

I though about doing this or trying to reset the ECU. I remember something about ECUs needing to be reset after a new component has been fitted...Have taken it to Lexus MK to see if they can diagnose the problem. The technician sat in it with me and thinks it has a misfire (crap plugs / leads / coil pack). These guys should be able to get to the problem even if I have to replace stuff myself later. This is the problem with cars, you need lots of time to tinker with them, if I had serious time I could have probably tried plugs and tried other stuff. I'm either away with work or on call so dealing with this takes a long time and has to be fitted in. Now I look back I maybe should have taken in straight to the Lexus guys, but then you could be spending lots of money sorting a simple problem. Otherwise it seems to be good...A couple of minor things I can live with or tinker with when I am free. Hi In defence of the Lexus service I can't say that I feel I have paid over the odds for anything they have done on my car in 16 years they will diagnose the problem a lot quicker than anyone else and they will tell you truthfully and precisely what needs doing before they will start any work or replacement of parts. Now if you then resolve to fix the problem somewhere else you have the option,and they don't fall out with you, in fact when I had replacement parts fitted to my LS400 back in 2000 The lexus dealership fitted the parts I had sourced in the USA charging only for the labour but with the proviso there was no guarantee on the parts or subsequent knock on effects to other components. I try to fix the fixable things on my car but inevitably there will come a time that this can only be done in a Lexus workshop and I think in my particular situation that will mean a new Lexus as the values of a 1990 or pennies and any serious engine or transmission fault would spell curtains for this old girl. I think you could have a point there ambermarine. The money I have spent with a local (although reasonable) garage chasing this may have been better spent having Lexus diagnose the fault in the first place. Having said that, they would have also found the duff oxy sensor and I would have had them change this. That would have been more expensive than having an independent do it.

I though about doing this or trying to reset the ECU. I remember something about ECUs needing to be reset after a new component has been fitted...Have taken it to Lexus MK to see if they can diagnose the problem. The technician sat in it with me and thinks it has a misfire (crap plugs / leads / coil pack). These guys should be able to get to the problem even if I have to replace stuff myself later. This is the problem with cars, you need lots of time to tinker with them, if I had serious time I could have probably tried plugs and tried other stuff. I'm either away with work or on call so dealing with this takes a long time and has to be fitted in. Now I look back I maybe should have taken in straight to the Lexus guys, but then you could be spending lots of money sorting a simple problem. Otherwise it seems to be good...A couple of minor things I can live with or tinker with when I am free.

I have changed the MAF sensor for a used unit today and the fault is EXACTLY the same. Looks like it will have to go to Lexus today.