jeepgirly1989

My 89 Jeep Cherokee (4.0lt) is having a very high 2100RPM idle.
We checked the throttle position sensor and it is perfectly fine.
Cleaned out throttle body.. completely.
When spraying Carb cleaner on driver side of the manifold near the #5 cylinder, the RMPS drop slightly but goes back to high idle.

It has such a high RMP at idle that the gears grind when placing the automatic transmission in park and the RMPS drop for a slight second but go back to 2100RMP.
When hitting the gas in park, the RMPs drop and it begans to back fire.
We did put a new header on it but we are not sure if the manifold leak on it is causing it to idle so high.

Any suggestions or ideas as to what it might be?
(we have never EVER had this problem with my Jeep before.)

bishop letov

I would gather that the intake and or exhaust gasket is leaking especially since you stat that sraying something near specifically number 5 causes a reaction. its usually due to a good vacuum leak and once that is corrected my belief is that itll even out. check the torque settings on the bolts. if I remember correctly a few of the bolts do infact tie in both the intake and exhaust manifold.