I bought a 99 avant quattro with 150,000 miles that has an annoying issue. Occasionally when giving it the gas it will stutter and act like it doesn't want to go, but I give it more gas and it usually goes fine after that. Also one time it wouldn't start when warm. I replaced the fuel filter, vacuum lines, and spark plugs, none of which fixed the problem. Now I am thinking possibly the coolant temp sensor, spark plug wires, or fuel pump. The previous owner had told me the #3 coil was bad, so that is a possibility also. There is no check engine light, and the temperature shows normal. Any advice is appreciated!

 

i would change the spark plug wires and if that fails i will also change the ignition coil. the reason is, after changing the plugs only, the resistance is too high for the old spark plug wires which turn to be leaking at this age, and there fore turn not to provide enough energy for a spark, this in turn causes the lack of power.

 

You really should check the codes before just changing parts. Yes, you can have codes stored without a check engine light.

If you have an Audi (or VW, Seat ect) and plan on keeping it, you should get a VAG Com or something that reads real VAG codes. It WILL pay for itself... even if you do not do the work yourself.

I think I saw a link for people who have one that will read your codes for you...

Failing that, many auto parts store will pull your codes, but may not use something that will read ALL of your codes.

 

Clean the MAF sensor with an appropriate cleaner. Clean the throttle body and go through a calibration cycle.

BTW, does your water temperature gauge read correctly?

 

IM with hxgaser. Clean the MAF sensor. If a coil was bad there would definately be a CEL on. Also, on a 99 2.8 each cylinder doesnt have a coil pack, so the previous owner saying that the #3 coil is bad is wrong.

The temp sensors can malfunction sporatically. They are very common to go bad but usually cause problems when starting and when the engine is cold.

If it were the wires you would most likely have a check engine light for a random or multiple cylinder misfire. If the wires are old, it would be better to change them anyway.

The problem could also be dirty/faulty injector. Dump a can of Seafoam into the gas tank next time you fill up to help clean the injectors/valves.

Easiest thing to do though is clean your MAF sensor. That is cheap, easy and could very well be the problem.