JDM obd1 B16 swapped into a 92 hatch. Just installed an aebs intake manifold and the car will surge. I cant get idle to go any lower than 1900 rpms and it will surge from 1900-1000, if i rev to 3k it will surge from 3k-1000 if i rev to 5k it will also surge back down to 1k, even under load. It throws no check engine lights. Any thoughts?

 

You probably have vacuum leak somewhere. The easiest thing to do is put your hand over the throttle body while the car is running. If the car does not cut off then you might have a loose bolt on the im or the tb. If the car does cut off then you have a problem elsewhere. I have seen many people install ims and just have a few bolts that were a hair loose. That little bit caused an air leak and the car surged.

 

if it were a vaccuum leak would it surge like that even under load at all rpm? also, when the car is warmed all the way up there is still a pretty good pull through the iac and when i plug it with my finger the car drops in rpm but will still surge.

 

bad pcv valve. Got it fixed and i must say i give 4 thumbs up to the aebs manifold, it now chirps 4th consistently.