idle issue

RedChuck

NAXJA Forum User
Location
Delaware
99 4.0l 5sp xj

ok strange idle. i need help with the diagnostic. check engine light came on the other night. o2 sensor 1 and 2 high voltage. and it was running rough got under found out sensor 2 the wire came out of the clip and was rubbing against the ujoint. it took the sheathing of the o2 sensor so i just taped them since the wire did not look damaged. and i also replaced the IAC because its been staying at high idle at lights for a while.

sooo it is still acting weird but no codes.

when i start it up cold it is fine and normal idle speed. i let it warm up and then it starts bogging down to maybe 600 rpm or less and just before it stalls it gives itself some gas and brings it up to 1100 rpm and drops all over again. i let it run like that for a while and it never corrected itself so i pulled the batt cables and clamped them together for awhile to reset the ecu. same issue after it sat for a while.


oh and i also changed the prv on the back of the valve cover cause i had an extra around and i though i could smell oil (could have been my garage though)
 
no i have not. i always thought the iac controlled it at idle and the throttle would be at 0%. but i did notice a power loss today while accelerating. i guess ill change that and go from there.

but this morning i threw some codes

p0141-fault- O2 sensor #2 heater circuit
p0135-pending- o2 sensor #1 heater circuit
p0138-pending- o2 sensor #2 circuit high voltage

does this shed any light?
 
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