90xj,99xj,92mj

k so like i said its a 90 4dr xj and the idle is just acting crazy! first start up is perfect but after you start driving it the idle will be way high and some times when you stop and put it in neutral it sounds like someone is reving it it jumps from about 800 rpm to 1200 rpm back and forward. im confused and dunno what it could be. in the last 2 months ive replaced the following.

tps, plugs and wires, o2 sensor, cat, did the 703 injector upgrade, and i also put seafoam in my tb and gas tank.
any help would be apreciated

scoob

check for vacuum leak test your map sensor try cleaning connections on your iac valve and last but not least test your egr valve just a few things i did with mine

90xj,99xj,92mj

i noticed the vaccum hose going from fuel pressure regulator to the intake manifold was loose and now the idl does not jump around but its still really high

scoob

if you get a can of carb cleaner and spray around the vacuum lines and the idle jumps around more than it already is then you have a leak somewhere

90xj,99xj,92mj

i'll try that, how do i check the map sensor, if u disconnect the vacuum hose the idle goes where it should be but smokes ha so

mike albo

also try cleaning your IAC real good to,mine was doing the same thing,tried cleaning first, then ended up replaceing it

90xj,99xj,92mj

sorry iac?

90xj,99xj,92mj

also what is this in the white? that black bolt is really hot i dont think a ground bolt would be hot, and is that the egr valve to the left?

scoob

that's a resistor for the fuel pump to quiet them down the thing next to it is the egr solenoid supposed to control when it's open and closed (i plugged my egr tube so it's all deleted)

90xj,99xj,92mj

can you post a pic how to do that