2001 Audi A4 Quattro, 1.8t: I replaced the coils on my ride and about 100 mile later I get CEL code P1128, Long Term Fuel Trim mult., Bank1 System too Lean. I guess it's running lean, I don't know, but what are some of the common Audi problems that would cause this code? Is it an injector issue, filter, or am I way off base?

 

I'd almost put money on a badmaf. The fault code is right. The time is right (7 year old vw product). I'm pretty sure thats the code I had when mymaf was shot. Injectors are never an issue (unless it's a leaky O ring).
If it's not a bad maf, you might have unmetered air entering the engine whcih could be from a vaccum leak. But, it would have to be a giant gapping leak to trigger that code. Look for obvious leaks in your vaccum lines around the intake manifold. But again, I'm saying MAF.

 

Do you have the readings from block 032?

 

I will try and get them tonight and post them. Thanks for your advice

 

I had a vacumm line leak when i had that code, (front side line on intake that runs to the DV).

 

Ok, I tried to read metering block 032 but my version of VAG does not allow it. I did get another code while I was in there,
P0321 Generic Ignition/Distributor Engine Speed Input Circuit Range/PerformanceI guess I will try and clean the MAF this weekend and hope that takes care of things. I'm not sure what would cause the above code, Any thoughts?

 

Never seem that code before, but it seems to be for the crank sensor seeing that it does say "engine speed input".

 

Ok, I pulled the MAF and cleaned it with alcohol and surgical swabs and reinstalled it. Now I get an airflow sensor low voltage code, I think P 0102 Mass or Volume Air Flow Circuit Low Input . CEL is back on but no driveability problems. the P1128, Long Term Fuel Trim mult., Bank1 System too Lean has not reappeared so I guess cleaning it helped that problem. Any ideas?

 

Sounds like the maf isn't plugged in or it is just dead now. When that happens the ecu no longer uses the maf readings to help set fuel trim. You need to read block 003 to see if your getting any maf readings at all.

 

Thanks Mike, I will check to see if it is reading and go from there. I will recheck my connections first.