Misfire/Hesitation

[whizzingalong]

Hi, my recently acquired car (2000 996 Turbo) started to run poorly and the check engine light came on. I took the car to my dealer and they thought it had an air leak. They replaced the MAF sensor and it seemed to cure the problem. However after using the car a couple of times it seems to have developed a different kind of misfire !

It seems to occur between 1500 and 3000 rpm. when using a small amount of throttle. It is most noticable at steady speed especially on the motorway when it feels like the engine splutters for a split second ! almost like the power had been cut for a moment !

Any idea what the most likely cause might be ?

Could it be the Lambda Sensors ?

Thanks

[fdorn]

did you read through this...

http://www.renntech.org/forums/index.php?showtopic=22132

I have an 01 turbo and this started last week. My CEL went on for about 10 seconds and then self-corrected. It still hesitates/stutter/misfires under high boost. You really need the codes. I taking the car next week and will let you know what they tell me.

http://durametric.com

[whizzingalong]

I did read that topic ....... Mine is fine at high revs and while accelerating. It's cruising along and going slowly it seems to have trouble with. I have just been looking at the Durametric website, it looks like a very usefull thing to have. I would be very interested to hear how yours gets fixed.

[fdorn]

I let you know, my stutter is under heavy acceleration/boost (above .5) right around 3500-4500 RPM. My car has 56,000 miles on it and I track it as often as possible. I am sure its MAF sensor, spark plus, and/or a air leak. It is perfectly fine when driving normal and like I said, the CEL is off.

Edited January 10, 2009 by fdorn

[wross996TT]

Hi, my recently acquired car (2000 996 Turbo) started to run poorly and the check engine light came on. I took the car to my dealer and they thought it had an air leak. They replaced the MAF sensor and it seemed to cure the problem. However after using the car a couple of times it seems to have developed a different kind of misfire !

It seems to occur between 1500 and 3000 rpm. when using a small amount of throttle. It is most noticable at steady speed especially on the motorway when it feels like the engine splutters for a split second ! almost like the power had been cut for a moment !

Any idea what the most likely cause might be ?

Could it be the Lambda Sensors ?

Thanks

Normal...variocam.

[whizzingalong]

Normal Variocam , really !!! what revs does it change at ?

[wross996TT]

if you are not on it...exactly as you are getting itread here

[ScottArizona]

I am experiencing the same thing, and candidly, do not know if its normal or not (since I'm pretty new to these cars). I too have changed plugs, the maf (and even cleaned the filter and changed the oil), with no improvement. Today I got a check engine light. Its at my tech as we speak and I'll know more tomorrow. I'll keep you guys posted.

[ScottArizona]

Well, the verdict is in. Pre-cat o2 sensor kaput. I knew it wasn't my imagination. When I get the car back I'll let you guys know whether the hesitation is gone.

[whizzingalong]

Hi Scott, looking forward to hearing if the o2 sensor was the problem !

I understand they gradually deteriorate over time before they actually fail. Some people have suggested they should be replaced every 30k miles to keep the car running at its best .

If it solves the problem on your car I will be changing mine immediately.

Good Luck

jay

[ScottArizona]

Hi Scott, looking forward to hearing if the o2 sensor was the problem !

I understand they gradually deteriorate over time before they actually fail. Some people have suggested they should be replaced every 30k miles to keep the car running at its best .

If it solves the problem on your car I will be changing mine immediately.

Good Luck

jay

I will let you know. I won't get the car back until probalby early next week, however, as my "slight oil leak" near the rms that I asked them to look at has now neccessitated an engine removal (breather hose above the tranny/engine, blew an o-ring). Scott.

[andymac]

Any update? Did the o2 sensor sort it?

[whizzingalong]

I put 2 new pre cat lambda sensors in mine and it runs much better now !

[andymac]

I put 2 new pre cat lambda sensors in mine and it runs much better now !

How much did they cost ?

[fdorn]

I let you know, my stutter is under heavy acceleration/boost (above .5) right around 3500-4500 RPM. My car has 56,000 miles on it and I track it as often as possible. I am sure its MAF sensor, spark plus, and/or a air leak. It is perfectly fine when driving normal and like I said, the CEL is off.

Dealer replaced spark plugs and it blisters again under heavy boost....so far so good.

Edited February 4, 2009 by fdorn

[whizzingalong]

They cost about £80 each.