Ok so this problem just recently happened. It started as my car would stall every once in a while but would run alright. Tonight i started it up and the RPMS were jumping all around. I started driving drove fine but then it barely would get past 1k rpms and i couldnt drive past 10mph. I could put the gas to the floor and it wouldnt react. I pulled over shut it off turned it back on and it acted normal. Started driving and it started sputtering and then kicked back to normal, i stepped on it and ran fan through the gears. I filled up the tank just in case it was a gas issue. Same thing happened. I can turn it on and it will sputter around from 1k rpms down to like 100rpms and back up some times stalling.

My first reaction is this was a fuel pump problem because the thing is acting like it is not getting enough fuel. Also when it would sputter around black smoke would come out of the tailpipe but if it ran normal for a bit the exhaust was normal

Any clues on this? I want to stress that the black smoke came out only when the car sputtered.

Its a 99 a4 with no mods. The spark plugs are two months old max, basically everything is new. It has 125k miles on it. IT FWD auto

 

try cleaning ur MAF sensor and throttle body

 

Ok i will check that. I did wanna note that i am not key on fuel pump problems/noises. But it sounded alright when i was listening to it, it sounded like an electric motor the whole time, but i guess that doesnt really mean its bad.

Thx for the fast response. I am really new to the Audi, but would a MAF sensor really make it struggle that bad. There was like 3 min where it would not increase rpms like it wasnt getting enough fuel.

 

ya. apparently it happens all the time to our cars. mine was jsut barely waving up and down b4. i cleaned th MAF and throttle body and now it won't even think bout doing it lol

 

The same happened to my 99 A4! Little by little, once and a while and then one day it happened but i couldnt get it started even though i pushed the rpm's/gas i couldnt keep it on.Now the car starts and runs good but 15min into the drive it starts doing it again till finaly it wont start.I have to wait 8hrs till i could start it up and it will drive for 15min and all over again.Im a Do It yourself type of person so i was wondering if you guys can give me a small description of how to clean and where to find the sensor that was suggested.

 

MAF is located after the airbox before the tube that leads into the engine. Its on the left side basically on top of the airbox. You need to remove the tube from the one side and I think guys spray electronics cleaner on it. You can search for it.

Original post sounds like car was jumping into safe mode doesn't it? I was thinking that it was something more than an MAF, like a bad coil pack or something. Throw any codes?





EDIT:
I'm too nice to you guys. Go here for MAF cleaning:

https://www.audiforums.com/m_379529/tm.htm

Its from those crazy TT guys, but its good general info.

 

I first thought it was the spark plugs because the car wouldnt stay on at all so i checked them and so they had oil around them and in the coils. I changed the gasket and the coils as well as the spark plugs.The car finally turned on and stayed on but now only for about 15min or more at times.