mitsuturbo
Well-known member
You can do some simple diagnostics to try and isolate the issue. The intake manifold is receiving too much air from somewhere. Choke off all possible entry points at the same time.
Screw the BISS all the way in and see if it settles down. If there's little or no change, then Check ALL your vac lines coming from the manifold. I'd suggest plugging ALL of them, and then start the car, just to see if it helps with the issue. Yes, that's right.. plug EVERY SINGLE PORT on the intake manifold. Even the brake booster port... If this helps fix the idle, then start re-connecting all the vacuum lines and see when the idle surge starts up again. If this doesn't fix the problem and/or point you in the right direction, then i'd suggest checking for leaks at the intake manifold flanges.. both at the TB and the head.
Screw the BISS all the way in and see if it settles down. If there's little or no change, then Check ALL your vac lines coming from the manifold. I'd suggest plugging ALL of them, and then start the car, just to see if it helps with the issue. Yes, that's right.. plug EVERY SINGLE PORT on the intake manifold. Even the brake booster port... If this helps fix the idle, then start re-connecting all the vacuum lines and see when the idle surge starts up again. If this doesn't fix the problem and/or point you in the right direction, then i'd suggest checking for leaks at the intake manifold flanges.. both at the TB and the head.