rolling idle

[dcjackson22]

This rolling idle is killin me every part that could be replaced on my car has been, the wierdest part about it is that after the car is warm it stops . i work in a shop and i looked on all data and did everything it said to do, i need help at this point no dsm guru's i know can figure it out either.

 

[rarson]

Did you check the VFAQ? There are a bunch of them that could help solve idle problems.

 

[kamronman]

MY CAR DOES THE EXACT SAME THING!! It idles fine warming up, then if i back out the driveway in neutral it will start to surge like ####ing crazy, same when coming up to a stop! But if the car's like totally hot it won't even surge it just idles at like 600 with -12 vacuum and 16.1 afr's. uhhhh what the heck! someone help us out, i've replaced the tps, and Set base idle to -5 degrees, then set idle using the BISS when it's completely warm to 700-800. yet the idle is never effing stable.

 

[nyTalonTsi]

Have you replaced the biss screw. Times the o-ring goes bad and it will leak.

Have you checked the vacuum hoses and such?

Also if you still have cruise, the cable from age becomes brittle and either adjust it and spray some lube on it or completely eliminate it.

 

[DIRQUIN]

With vacuum that low it sounds like a vac/boost leak. Mine a 650-700 rpm runs -18-21 in vac. Check for any leaks.

 

[kamronman]

Ok, i'll check for leaks, i know theres a tiny hole in my valve cover, could that cause a leak of vacuum? it sure is leaking oil on to my spark plug wires.. i tried to seal it up with rtv but didnt work. So I'll try a vac leak test i guess.

Ok i just tested for vacuum leaks and i found one in my tial 38mm external wategate! It failed the test misserably

 

[bkrathwohl]

Ok i just tested for vacuum leaks and i found one in my tial 38mm external wategate! It failed the test misserably

Thats great that you found where it was leaking out at. Fixing that leak should theoretically fix your idle issue unless you have another leak somewhere. My car does the exact same thing, I'm positive its a vac leak I just haven't checked it because I'm lazy.

 

[Maas]

ISC, FIAV block off......

 

[DIRQUIN]

Did you get the leak fixed? Did it fix your idle issue?

 

[kamronman]

Ok, i got a hold of a vacuum gun to test everything. My wastegate failed the test, but even unplugged my car is still acting funny. So i put my ears on and i could hear a faint hissing coming from around the throttle body somewhere, i'm positive i just have a vac leak, so I'm gunna replace all the gaskets and inspect the throttle body or get a new one this snowy season!