Rough Running Is220D

[pupster]

Good morning everyone,

I am having no end of troublr with my 2007 IS220D. I posted a topic about rough running in the 2000 RPM rev range and since then things got somewhat worse. Apart from this rough running the car developed a severe missfire and was eventually traced to a fault injector. Prior to all of this I replaced and checked the following.

1. Air Filter (very dirty)

2. Checked the EGR valve (very clean) but gave it another clean whilst it was out

3. Replaced the fuel filter (very dirty)

4. Added fuel additive as reccomended in other forums and a Turbo cleaner additive.

I took the car into a lexus dealer who ran all of the diags and they all passed but they slammed the car for other minor things which I can quite easily do myself.

Now the injector has been replaced i am back to square 1 again with this rough running especially when I am doing about 80MPH it still feels like a missfire and not what I expect from a Lexus. I am slowly running out of ideas and certainly do not want to spend any more money than I need and would welcome any good suggestions. As an ex mechanic I am feeling as though it is another injector not working correctly but I cannot prove it and wondering whether I should buy a new one and try it systematically in the remaining 3 cylinders.. As a side line since the injector was replaced on Cyl 1 my MPG has improved slightly but nowhere near what it should be.

Any suggestions

[normski2]

Don't be too surprised if you don't get many replies. This could be a whole host of things. Could type 150 lines and still not cover the possible reason. You may well be right on the money with the injector. Any evidence of soot around them? Take the engine cover off and take a peek.

As an example. My son had my 220d when I moved up to the 250. He had a really lumpy misfire/acceleration problem...it just suddenly went gutless.It was all he could do to get from Bristol to Dorset. There were no Dash warnings of anything untoward. I feared injectors from what son described.

We took it to my local friendly garage who linked up his laptop and it pointed us to (something like) Oxygen sensor no:2 fault. When we investigated the sensor we eventually found a crimped wire on the feed in. It was barely hanging by one strand of wire. May have been clonked by a socket head/spanner....who knows? Anyway we stripped it back and repaired it and she ran as sweet as could be.

[pupster]

Thanks Normski,

I'm going to have a poke around at the weekend to try and find anything "Silly" When I looked a couple of weeks ago all of the injectors seemed pretty clean to me (no soot) but I will have another look. If I cant see anything obvious as you suggest then I will have the 3 remaining injectors checked and cleaned and have already contacted Carwood to see if they can do me a day service.

I really love the car but this is driving me mad but I do have a local garage with good mechanics and diagnostic tools that I might take it to at least that way I am not ramping up a huge bill. On my last Lexus vist they were going to do a DPF re-generation but the last mechanic said it did not need it I guess they are as baffled.. The interesting thing was that with a little fault like this they were trying to sell me a new car (very suspicious)....

[pupster]

Sorry Normski,

Had a look at the lexus repair CD but cannot find any reference to the oxygen sensor where are they located ?

[normski2]

If your local chap can get in with his Techstream or whatever, he can instigate a forced regeneration. It's quite simple. Makes the DPF red hot and burns all the carbon/soot out....so it does smoke a wee bit.

[normski2]

This one was at the front of the engine slightly to the right and sort of behind the pulley area. Two wires going into a circular cap...as i recall.

[pupster]

Thanks I'll start there and work my way around.... Much appreciated.

[normski2]

Check the wires into the EGR valve too. That plug is pulled out a fair few times...if that's been compromised it will affect the fuel/air mix.

If you can be arsed to check the EGR again ...I know you said its cleanish....but is the piston seating itself properly onto the rim? That again can have an effect. Check the back end of the device for any rust inside...again that can have an effect...think it was 3 little torx bolts.

[pupster]

Nice one Normski ,

Think I will make a start there and work round to the other things. Gonna buy some contact cleaner and clean all the connectors one at a time to the injectots and anything else i can see. Might even give the MAF a squirt I know they are reliable but never overlook the obvious... I know that this is a simple fault to rectify but it's just getting to the right place. Nothing like the good old fashioned methodology of the old cars lol.... Plus point rotor arm distributor cap days......