2000 rpm idle in park.

[Mechatron]

Heys folks! I have a '92 Eddie B. Starts, runs &idles fine at first. After running for a while, When I put it in park, The rpm's jump to 2000! Took off IAC and cleaned & reinstalled. Was fine for a couple of weeks. Last night I got home, put it in park, and the rpm's jumped to 2000 once again. I have 250'000 miles on the engine. Any suggestions?

 

[bluesman2333]

It still could be the IAC. The first thing I would check is all the vac hoses. If everything looks good then spray some ether IN SMALL QUANTITIES around the intake to see if it is a vac leak. The engine will slightly rev if you have a leak. Intake leaks are common on 4.0s. If everything looks good then, replace the IAC. I'm saying this because I went through this on one of my X's and even though I cleaned the IAC, it still acted up soon after and the replacement fixed the problem. I did have vac leaks from bad hoses that I fixed, but the problem finally totally went away after the IAC change.

 

[Willard]

Just for reference, does it idle around 500-700 RPM in gear like it should?

 

[Mechatron]

Thanks for the info. Yes it idles between 500-700 in gear.