hello guys,
for starts i have a 1999 audi a4 quattro 1.8t 150,000 miles
now heres the problem and i think i caused it i just dont know what i did so here it goes....I had a exhaust leake at the flex pipe 2 months ago and replaced it with a straight pipe i know now that was a bad idea cause after that the large muffler looking thing in the back started to rattle so i decided to tie it off so it didnt do it anymore then the big problem happened the catilic converter snapped off of the flange that was attached to it so i thought i could just weld the cat back to the flange i did this with the battery unpluged and it still in the car now the weld is holding but when i went to start my car it starts then the rpm's drop realy low and the car shuts off. if i rev it up a bit it during start the rpm's will drop then go back up etc.. until it comes to a normal level i have then drove it and it does not feel like it has any loss of power but when i stop again at a red light or stop sign the car's rpm's drop and do the same thing where it levels itself out or it stalls out. my check engine light isn't on when i have the car running it is only on after the car stalls out also when the car's rpm's drop before it stalls my battery light flashes as well but neither light are on once i get it running any help would be greatly appreciated

 

If it smells like exhaust, I'm going to guess (since there are no codes) that your CAT is clogged.......it may have happened when you welded it back on....

 

Might need to adapt the throttle, plugged cat would be low on power.

 

how wouuld i go about adapting the throttle

 

Here's a link to manually adapting the throttle body. It doesn't always work manually-you would generally need to use the VAG COM software to do this:

Throttle Body Adjustment - Holy ****, makes a different

Here's an other link from this site on the throttle body as well, has the link on how to reset throttle body via the ROSS tech site with the VAG com software.

https://www.audiforums.com/forum/diy...g-idle-160531/