I hate to have my first post be a problem. But anyway...
Relevant Info:
2001 Audi A6
2.8L Engine
Quattro
67,000mi
No CELs showing

So today my 2001 A6 decided to be a bastard. Started up normal, ran fine until I got into down and then **** went all batty. Now the car refuses to idle properly and sounds like a Honda with a fart pipe past 4000RPM.

I noticed a little bit of "farty" noise while idiling coming from the passenger side while, behind the engine so I am thinking there might be an exhaust leak. However I am thinking spark plugs or some ECU **** up too because the car has NO power below 2000RPM, then when it hits about 2500 it's *****-to-the-wall. I don't know if an IAT or screwed or something too since this is the first cold day we've had this season.

Or worst case scenario the timing belt has skipped or something equally bad. However I'm thinking if the timing belt slipped it would have eaten some valves in the process. Any ideas?

Cliffs:
Car won't idle
Sounds like ****
Runs like ****
No power below 2500RPM
...
No profit

 

When my car's MAF needed replacement it ran poorly as yours.
I had a CEL and P0102 code however.
I'd do a SeaFoam treatment, then a throttle body alignment.
Good luck.

 

Well how am I to tell if the MAF is bad if it is not throwing a CEL? Also what is this "throttle body alignment" you speak of?

 

sounds like you broke your exhaust... usually around the flex pipe

I wouldn't worry about the MAF being bad, maybe dirty... w/o throwing a CEL.

 

if the element inside the maf starts to degrade then you wont set a code necessarily. but it will not give you the proper amount of air flow and ecu will compensate with injector pulse on the wrong information your maf is sending.

 

Any chance I might have borked it while I was installing the air filter? Is there a way to test the MAF with a multimeter? Because I would sure as hell like to check what I can before I have to towed to the dealership and have to mortgage my soul for repairs.

 

yep.. you need to first get some base line readings to compare with... like what your maf voltage should be at idle and then like at 2000 rpm or something. then find your maf signal wire and see what the voltage is at those speeds and compare. and yes doing an air filter you could have handled it a little rough and caused a malfunction in the maf...

 

Greetings,,,Have you resolved your rough idle issue? I ,too, have a 2001 A6 2.8 L quattro and that has developed rough idling for a month or so, now a steady CEL, Autozone pulled the P0102 code as well as P0170. I tested MAF possiblity by switching my MAF with a MAF from properly running 2001 A6 2.8L. It didn't help the rough idle at all, so I am thinking either I have 2 separate issues --rough idle from cause other than MAF, and an MAF throwing the code? or a non MAF issue which causes rough idle that also throws the code. If you have learned anything from your vehicle's rough idle that could help me, I'd greatly appreciate any info!
Best Regards, Mrs. A

 

Yeah the problem was that I was an unobservant moron when I replaced the air filter. One of the intake hoses behind the MAF was barely attached to the intake plenum. So all of the air that SHOULD have been going into the engine was instead going...nowhere useful. All I needed to do was re-attach the hope and everything was fine. I'm not sure if your problem is similar but it wouldn't hurt to check and see if all your intake pieces are clamped on tight.

 

anytime you have a p0170 or a code close to that it has to do with fuel trim, how the ecu decides to fuel the vehicle, whether it be to lean the mixture or to make it more rich. i think p0171 is lean.. and im not sure what rich would be.. but any way. on these newer cars usually the culprit is a bad maf sensor or a hose(as in the last mentioned quote) has come loose and is causing the system to run lean.. then the ecu tries to compensate and correct with a positive fuel trim. when the maf degrades it does not read the proper amount of air into the system and says the amount of air coming in is .. lets say.. 2x.. when in fact it is 5x.. so then the ecu reads the o2 sensors showing a lean condition because its bringing in over 2 times the amount of air into the mixture....so it widens the fuel injector pulse width for more fuel to correct the issue as best as it can.. but of course without properly functioning sensors or leaking past the sensors it is impossible to run perfect. and remember people.. these arent your 1969 fords anymore.. the government wants these newer cars to run as effieciently as possible....