High Idle at start

[LittleD]

For some reason, the jeep will randomly start and idle around 2500 rpm, after a bit (maybe 2 min) the jeep will then idle at the norm at around 900 rpm. I replaced the a.s motor on the tb, all the vac lines are connected and there seems to not be anything that triggers this.

It's a 89 xj, 4.0 straight six.

[clean4drxj]

try cleaning out your throttlebody but use something thats safe for the sensors

[LittleD]

Bump.

Im noticing that this usually happens in the rain.

[hoggie101]

could it be that its just warming up i no my bronco will idle at around 1500 for a little then dorp to normal when it the temp gauge moves

[LittleD]

It idles at 2500 rpm, i have to push down on the break as hard as i can to keep it from launching.

[breadtruck driver]

Check for vacuum leaks.

[doubleuj17]

X2 on the vac leaks and cleaning the carbon from the throttle body and iac passage

[Sphinx6211]

most likely a coincidence its happening in the rain, replace the 2 sensors on the TB for under $100 is something i would do... If you replace any one of these, it is recommended that you disconnect your battery for at least 15 to 20 min, which should clear old codes and will allow your computer to learn the new TPS sensor etc...

Keep in mind, first few times you drive it around, you can expect some sluggish behaviour until the computer learns the new sensor signals.

[Kyle]

My 87 had the same issue, i never figured it out before i sold it because it seemed to have stopped. I hope you get it figured out.

[LittleD]

Bump, replaced the a.s motor, and it is still idling high when in park/neutral. Could this be a tps issue?

[LittleD]

Turned out to be a bad tps, went to swap the spare one in, and the bottom bold snapped in the throttle body, top bolt is holding it on well, and now i have to do a few more adjustments since when i step on the gas from a stop, the jeeps almost stalls.