So, I have a friend who has an 01 A4 1.8TQM. It has about 115K miles (I think) and it has a lot of problems. One it just sounds bad. I am pretty sure he has a bad exhaust leak. It also has a hard time staying running. Before it completely died, he could not get it over 50 mph and it would barely go up hill. He got a flashing cell once (Blinked a few times then quite) so I know he had some type of misfire. He has a check engine light on that is a code P0171 which is a system lean code. He previously had another code that said something about the FPR (which I didn't see so I don't know for sure) but we replaced that and now he is getting the system lean code. It drove for a while now it will start and idle but as soon as you hit the gas it sputters and dies. I am thinking bad injectors or possibly fuel filter. Also he might need new plugs. Im not sure though. We are going to attempt to get the car to my house tonight (about 15 miles so who knows what will happen) so i can try and fix it in a garage. (I'm not working outside in 30-40 degree weather! LOL). Any ideas on other things I can look at? Oh and he has not changed his oil in about 5 months. Thats the first thing I am going to do. We also ran some seafoam through the engine in his gas tank. I am going to seafoam the oil and through the intake mani as well.

Josh

 

I would start with a oil change, spank plug change, check for boost and exhaust leaks and most importantly, a compression test. That should narrow down the problem

 

ok, sounds good. or the compression test how do I go about doing that and what are the numbers I should be looking for?

Josh

 

Someone just did a write up for it here a couple weeks back in this forum.

 

Thats right, I remember that now. I will search for it. Thanks.

Josh

 

here it is

 

I know this is out of the way here, but is it good and effective to use seafoam for the car? I mean, it looks pretty dangerous by viewing some vids. Because I have glogged cats and just purchased a remus exhaust and 2 new magnaflow converters. After I install them is it worth using it or not?
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if done right it is perfectly safe

 

Vacuum leak.

https://www.audiforums.com/m_527562/tm.htm

 

Yup but there is one thing Is the foam in the tank at this exact time? If so RUN IT OUT. This same thing happened to me when I foamed my tank turns out I had alot of crap in the lines and such from the former owner and probley 7-11 gas. If its not in the tank the I would go with oil, plugs, and check to see if the air intake is clear. I've had a bag get sucked in and cover the filter on an old car that was a fun night.