I just changed out my exhaust to a racing beat (header,cat,catback) and now im having a problem with power band issues. When i keep the throttle steady the car surges on and off with power. If i'm at a stop and go easy on the throttle while letting off the clutch the revs will drop down and then catch at around 700rpm and then kick back up. I'm not sure how this could change by switching out the exhaust thus the thread. Thanks in advance for the help.

 

s4 or s5?

 

91 vert s5

 

everything reconnected properly? SOunds like a vaccum leak of some sort. Check over the areas with carb cleaner and spray and see if the idle changes with the car on.

 

look for an exhaust leak, sounds like when my downpipe bolts backed off a bit - wasn't enough to make a racket or be continuous, but bumps and just vibrations caused hiccups and sags in power - I thought I had a spark/timing issue. These cars are very sensitive to exhaust leaks.

 

Thanks for the advice. I dont think its a vacuum leak as the idle doesnt hiccup or surge. Racerca: that makes sense, i thought it was a timing/tps issue as well. Ill double check for vacuum leaks and see what happens.