I haven't had an issue the past few weeks since I got the my car (s4 turbo ii) but I changed the oil recently and while driving around I noticed that my idle has raised itself.

I'm thinking it maybe a tps issue but it could also be a vacuum leak since I just had the boost gauge fixed. Any ideas? Is it common for the tps to be out of adjustment every few thousand miles?

The motor is street ported so the idle was never regular anyway but it shouldnt hover just over a 1000 and return to normal pretty consistantly if I apply no throttle and slip the clutch with the e brake applied...

Also my horn works when it wants to not sure if it's the cpu or just that the buttons are 24 years old

Any suggestions from experience are greatly appreciated

-Thanks

Steven

 

Most street ports that aren't ridiculously huge should idle just fine at under 1000 RPM. The stock ECU is very forgiving to porting changes in the "street" range.

If the idle has raised itself then it is most certainly a vacuum leak, or something stuck physically on the throttle body (I have seen a lot of stuck TII throttle bodies lately). Make sure nothing is binding, clean the linkages thoroughly, then apply white lithium grease. Drive around for a while, then clean the grease off because it will become a dirt magnet. Lubricate with dry lithium grease (such as would be used for locks).

And of course, check for any vacuum leaks.

Once you are sure the throttle body is unstuck, adjust the TPS.

 

I'll work on it on my next day off. Thanks for the informative reply.
I'm pretty sure it's a vacuum leak since it didnt start doing this until I had the sending unit for my electric boost gauge replaced.