scavengerj

FSM for my 00 4.0L I6 indicates the minimum air flow idle rpm should be between 500 and 900 rpm.

4jeepers

My '88 XJ will cover ALL the RPM ranges that you guys have posted in this thread. It all depends on what day of the week it is!

aj6

same thing for my 2001

it seems that newer jeeps idle higher?

ZaKingHunter

Yall mean there's a such thing as "normal" for Cherokees?

My375hp302

650, unless the IAC is acting up again and then it's 3500+

ken72

Well I changed my IAC this weekend and after the computer reprogramed for the new IAC the Idle still sits just below the 500 mark. It seems to idle a little smoother still but still low. Maybe a bad o2 sensor? No error code other than the classic p0455. I keep meaning to seafoam the engine but I need to do it at night.... dont want to make the neighbors mad. I am starting to think its just the way the engine runs.

Whats odd is after I installed the IAC the idle ran just above 500 and engine temp never went above 210. The idle would kick up to 1k when shifting from drive to park but would quickly drop back to about 600. I drove it around for about 45 mins like this thinking everything was pretty good. I came back to drive later that afternoon and the idle was back to below the 500 mark. I guess the computer was reprogramming for the new IAC.

Gunnar89

well mine cant make up its mind. its normaly 300-500 rpm. but some days for some reason it wants to idle at 2000-2500 it gets anoying when i step in the clutch at a stop light or sign and it sits there revving high but about 30 min of driving it goes down to 1000 than lil more driving back at norm 300-500 i feel like im drvin a toyota when it does that lol im glad i have a clutch

96_xj

this is the fun tho! cause it means our standard 5 speed cherokees have cruise control! it just sucks to find out when you go to engine brake and you dont.....

Gunnar89

lol thats exactly what i use it for when it happens lol

breakthecycle128

My 5 speed '93 XJ 2.5 sits at about 750rpm

ken72

Any suggestions on what could cause my idle speed to be so low. Could I have not reprogrammed the engine properly or something for the new IAC. I read on a ford forum to unplug the battery and then turn on the lights to drain any power remaining in any sensors. The after about 10 mins, plug it back in then turn the key to on for about 3 mins then turn on. Run the engine to operating temp and then 30 secs with ac on and then off in both park and then drive to relearn the new IAC. I cant find a vacuum leak but that should cause it to idle too high. Maybe an O2 sensor is going bad? When the idle speed is up the engine runs fantastic but at just under 500 rpms it feels like crap.

DangerWillRobinson

95 4.0 5spd sits smooth at 450.

Lugnut

ken 72 HOW FAR IS BRENTWOOD FROM CLARKSVILLE?

ken72

Looks like about an hour

XJTrey

Ugh story of my life -__-