Replaced MAF and now has a misfire

T

ThePocketGT

Member
Had the check engine light come on. Ran the OBD and it was the MAF sensor code. Reset and it repeated the same code 40 miles later, this pattern occurred two more times.
New MAF sensor installed, took for a drive and seemed good. Arrive home after 20 miles and when I stopped the engine started to misfire and rough idle. Ran the OBD and it brings up a new code 29D1 misfire on cylinder 5! And 2C7F 02 sensor downstream of cat.

Has anyone experienced similar and been able to resolve?
 
I'd guess the O2 sensor code is due to unburnt fuel from Cylinder 5.
Try swapping the coil to a different position and see if it moves the code to that cylinder.
Never discount coincidence.
 
enuff_zed said:
I'd guess the O2 sensor code is due to unburnt fuel from Cylinder 5.
Try swapping the coil to a different position and see if it moves the code to that cylinder.
Never discount coincidence.
Click to expand...

I thought the 02 would be due to the un burnt fuel,
I'll try swapping in the morning and see what happens.
Thanks
 
Ditto what enuuf z said.

If you need new coil packs for it,the proper Bosch ones from Autodoc are the cheapest I found,if you wait until the 38% discount code via the Autodoc App. (It's usually on most weeks).
Hope you get to the bottom of it :thumbsup:
 
I also have a box with a few decent second-hand coils if you only want one for diagnostics.
 
Update.
Switch the coil pack round and it didn't switch cylinder. Checked the spark plug and it was darker than the others. I thought unburnt fuel, which is the same thought for the o2 sensors. Replaced plug, cleared the code and went for a drive. 40 miles later, which was a mixture of cruising and driving hard... ran the obd reader again and no codes.

Praying its sorted!
 
I hope you've got it fixed then. :thumbsup:

If you do end up needing a coil pack I'm not too far from you and my 3 Series came with a spare set for an N52 engine so just let me know.
 
Coil pack seems the usually the culprit, otherwise a bad plug could have been the issue since you changed it and so far so good. Out of interest what make was the Maf replacement that you fitted?
 
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