Hey good ppl. The old 96er is having a hissy lately (96 XJ 4.0 with 230k on the spinner). About two months ago she cranked and started normally, but seemed to be idling a little rough. I thought it was my already bad engine mounts just getting a little worse and didn't think much of it. So for the last 2 months, up to 10 days ago, it's only symptom was starting ok but consistently idling rough.

So 10 days ago I changed out my fan clutch chasing down a separate variable engine temp problem (which involved loosening and re-tightening the serpentine belt, don't know if this was a contributing/exacerbating factor, possibly not related at all) and when I go to start again it just cranks and cranks. First crank is 5-10 sec with no engine response. 2nd and 3rd crank the same. 4th crank it gives a half-hearted sputter and quits. After 2 more cranks it barely gets going after some pedal feathering and a prayer. When I step out the ca I smell gas, so I chalk the hard start up to a flooding issue, although no clue what caused it.

Ever since that recent hard start the engine has started relatively ok, with about .5 to 1 second of extra cranking for insurance, but the idle has remained high around 1k for the entire duration when the engine is running until I shut it off. I thought the engine somehow needed to 'relearn' the correct fuel mixture and it would eventually work itself out. I was wrong. 10 days now and the idle stays high no matter what. When I'm driving and let off the gas it just continues to propel itself forward due to the high idle, and I'm having to mash the brake pedal noticeably harder to come to a stop.

Any idea what this is? I'm hoping it's as simple as a MAF sensor or intake cleaning.

I'm all ears. Thanks.

 

Do you have cruise control? A while back I had issues with high idle because the CC cable became "stuck" and would keep the idle high until I mashed the throttle and let off quickly. Sprayed some lube in a can down flex cable and it started working normal.