Hey guys, one of my friends has a 97 1.8T with APR stage 3 with some idling issues. When idling the rpm's will bounce around, sometimes it idles too low (like 400-500), and it has stalled from this before. Also, after filling up the gas tank it will idle funny. Most concerning is the fact that she's not throwing any sort of codes, no CEL or anything. Should I still scan it with vag-com?

My first thought was checking the spark plug gap because stage 3 runs a gt28, but they're already at .026. I'm inclined to think it might be her evaporation purge valve, I've seen a video of a B5 with a bouncing tach and the poster said that replacing their EPV fixed it.

I have a 98 1.8T with a perfect EPV, should I just take mine off and test it on her car to see if that's the fix?

Any help would be greatly appreciated. Below is a link to a video of her tach while driving, clutching and letting her rpm drop to idle.

idle problems - YouTube

 

Bump.

 

dont be concerned with the evap system. you could literally take it all out and nothing will happen. id look into either a vacuum leak or throttle body first. how does her car boost?

 

^this

Do you have more info on the plugs (miles, brand)? And have the coilpacks ever been replaced?

 

Also might want to try a throttle body adaptation.

 

it boosts just fine. not thinking its coil packs either. i'm using the plugs that apr recommends. about 155K on it.