AudiSportB5S4

Alright, so I have this *issue* of a fluctuating idle like it won't sit DEAD @ 800 it goes 760-800-840 and through that cycle etc... I've done lots of things did all the possible misfiring things etc, its not that. Yesterday did a real good pressure test, nothing, solid as a rock... Now on 2000's we have that goofy little check valve in the firewall that runs a beefy vac line to the back of the intake mani... Today I replaced the one time clamp that audi has on there with a screw style, and still.....

My vacuum reads 19 in HG. Sometimes I get 20, but I have an RS4 Airbox/Meter/Intake tube, which someone told me that since it's larger it pulls in less vacuum ?? Not sure if that's on par or not.

Anyways, tonight with my motor running I listened to the valve and I can hear it hissing... You think I should order the part and toss it in or does that valve never really go

Audi8myBM

When was your timing belt changed last?

AudiSportB5S4

within 10K... it was done when the motor was out for stage 3 install

S40RCE:Smurf

What kind of injectors do you have.

AudiSportB5S4

green giants. they are turned 90* every one... i can hear the check valve hissing thats the thinggg

turbosquatt

The hissing might happen because it doesn't seal well inside that rubber grommet. FWIW, I only get 19-20 in Hg of vacuum, and I believe that is standard idle vac. That may be a separate issue from the jumpy RPM's...

Throttle body maybe?? Does your throttle valve angle move around without touching the pedal?(VAG-COM)

AudiSportB5S4

What block is the throttle pos.? I will check that out just to see

S40RCE:Smurf

FYI, Bigger injectors tend to have a a 760-800 fluctuation

AudiSportB5S4

oh really... hmm OK... i mean it only is @ idle my fluctuation other than that car is 110%

turbosquatt

Block 003...