1st post long time looker
I've had my 88 jetta 1.8 single overhead cam for about 3 years now and I love it.
I keep having this problem: At idle in neutral my car idles up to about 2k then drops to 400rpm then repeats.This surge continues untill i midly hold the gas down and atempt to stabilize. then it smooths out and i can take my foot off{sometimes when its warm only}

tottally a mistery to me. I'm good with cars and can ussually figure anything out but this one has got me stumped.

I'm actually about to take it to a repair shop, herecy.

all help appreciated. thanks terry berry

 

Have you checked for a vacuum leak? Or could be the idle control.