alex2004

good afternoon everyone.

I have w211 2007 e200 kompressor, occasionally i get the check engine light (p0171 code) and after a few days it would go away for a few days and then come back. On idle the engine tries to stall and then the revs would jump to about 1500rpm and stay there. This thing would keep on happening while the car is stopped. after it happens for a few times the check engine would come up with that p0171 (system too lean) code. When the check engine is on the car seems to be running fine even when stopped, the revs would be as it should when idle (around 700 or so). then after a day or so the check engine would disappear and the stalling problem will start again, and so on.

Other then that car seems to be running fine.

Stage 1 - Engine tries to stall at idle and the revs would go up to 1500 +- rpm to prevent the car from stalling

Stage 2 - Check engine comes on after a day or so since stage 1 began. The car would mostly be running fine, occasionally trying to stall at idle.

Stage 3 - After about 2 days the check engine came on (stage 2), it would go off with car running fine

Stage 4 - The car would be running fine for about a day or so and then it would start again (stage 1).

After browsing Internet the only thing that I could think off is the MAF sensor playing up. Any ideas guys, I would really appreciate.

samaritrey

I assume you have the m271 engine. Could unplug the MAF and see if the car idles better. When the MAF is unplugged the car uses a default map which can help diagnose a bad one. Also the m271 is known to have a bad hose.

https://mbworld.org/forums/c-class-w...sible-fix.html
DIY for the hose
https://mbworld.org/forums/c-class-w...placement.html

alex2004

Thanks for your reply. It worked, I have unplugged the MAF and the car runners perfectly. Can I drive the car without plugging it in or do I need to replace/clean MAF straight away?

samaritrey

Depending on how many miles you are at I would probably just replace it but you could try to clean it using the proper procedures. Either way I would try to avoid driving it unit the issue is taken care of.

baumnutde

Hello, wondering if you ever fixed the P0171 issue with your car. I'm still having an issue with my 2004 E320. I've replaced the MAF, replaced the EGR valve, replaced several cracked hoses, replaced the front 02 sensors, fuel filter. However, the codes are still showing, now I'm getting a stall at the stop signs and have to try 2 or 3 restarts. I'm waiting to do a smoke test to determine where the vacuum leaks are, but I was wondering if anyone has an insight into what I might have missed. This issue has been going on for 3 months now. I have 156,000 on the odometer and this is the first time I've had any major issues with the car. Thanks, in advance, for any advise. Duke