i got a buddy of mine with a 99 d16y8, he is having the same issue. It will bounce rpms from 1300 to 1900 when cold. once it warms up it runs at about 900 rpms. He goes out to drive it, and the rpm bounce continues. We have done the coolant flush and bled the system. The tps sensor and gasket replaced along with iac sensor, o2 sensors, and timed it. Still acted the same, today we replaced the intake manifold gasket, checked for vacuum leaks and it checked out good. Went out on a test drive and it acted up again. Now we are at a stump, no clue what to check next. Ideas?

 

test the sensors(tps, map, ivac) with a multi meter, make sure the voltages are within spec,

when you clean the ivac, are you rotating the assembly 360 degrees, if it only goes up a bit, down a bit.. its bad..

 

Thanks, I will have to test that out see what they read. This car has started to become a big headache

 

ahh, don't stress it.. just take it smart and slow, fixing is the best part of something being broken