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excessive idle

rocklobster87

NAXJA Forum User
Location
eugene, or
97 ZJ, 4.0, auto. Purchased this vehicle non running and found pcm to be faulty. Had the local jy track one down for me and swapped it in, and the jeep then ran and drove perfectly. I drove it for a few days, no codes, no issues of any kind. I pressure washed under the hood briefly and drove some more. The next morning i went to turn it on and the idle raced to 2500 rpm and remained there. Checked for vac leaks. When i remove the intake pipe and block part of the iac passage in the tb i can make it idle normally. Swapped in a known good iac from same gen 4.0 and found it to make no difference. With one iac in the tb, and another plugged into the harness and in m hand, engine idling at 2500 the plunger makes no outward movement as it should to block the passage, but instead just clicks once every few seconds. I checked the 4 wires to the pcm for continuity and all were fine. At this point im assuming some part of the IAC driver circuit must be malfunctioning within the pcm, can anyone think of anything else that might cause this? Thanks in advance,
-james
 
Wet TPS = idle/ trans problems.

Agree, good place to start.

Might want to check and see if you knocked off any vacuum lines when pressure washing.
 
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thanks guys, im new to this forum which is why i accidentally posted this in the tow rigs forum and not oem tech, but im glad it still fell on some experienced minds.
 
thanks guys, im new to this forum which is why i accidentally posted this in the tow rigs forum and not oem tech, but im glad it still fell on some experienced minds.

Actually, you got moved from OEM to this forum because your rig is a ZJ, not an XJ/MJ--ergo "Other Tech".
 
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