norcaljim

Hi i have a 1991 audi 100s i have a few ?'s

1 when i bought the car at first it had a hesitation only while giving it gas from a dead stop i guess the only way to describe it would be give it gas stumble stumble and then it would take of and run fine until you come to a stop and then you do it all over again .now it has a exhaust leak so i took it to a muffler shop to have the leak welded and he did it but said that the cat was dam near glowing hot from a 6 block drive and he said he believed it to be from how bad it was running . so 5 days after the fix the car is leaking again (Cracked exhaust pipe ) and now barely running it idles so low that it just barely stays running but once it gets going the car flys . so does anyone got any ideas where to start

and my last ? is the radiators resivore (sp) has all this dirty looking film coating the inside of it is this normal and do i put anything in the tank beside water sorry for making this so long its just have no idea where to start thanks james

paudi100

maybe try cleaning the idle control valve? procedure in this forum somewhere. it's easy. changing the fuel filter - also easy. or maybe something else less easy? i dunno. what i'm slightly more confident of is my theory about the dirty looking film in the radiator resevoir. i'm guessing that someone put some radiator stop-leak stuff in there, which leaves that sort of crap behind. flush and refill with new water and coolant to get rid of it. if a new dirty looking film appears, that's probably just your radiator disintegrating.
p

kinderutz

this is the C4 body style 92 and up.... yours is 91...wrong forum...however a tune-up can only help...fuel filter, air filter, new oil and oil filter, plugs, wires, O2 sensors,clean and lube the idle control valve,check for vacuum leaks....all the small thing count and all these are very easy to do
cat nearly glowing from 6 blocks drive?...that can't be good...could it be running too rich? plugged cat?
good luck!