YJ idle problems

[Mredling]

I have a 1991 wrangler yj 4.0 and when i first start it, it wants to rev around 1500 and then drops to around 700 and after idling for about 2 minutes it acts like its going to die and then picks back up to around 700. I replaced all of the vacuum hoses and the fuel pump and fuel filter. My next guess would be idle air control valve or throttle position sensor. Any ideas on how to fix this without spending more money?

 

[Rebel_Frontier]

Check engine light on? It can be anything from your pickup coil to your spark plugs to your throttle position sensor. If your check engine light is on, you may wanna hook up a computer to it as that will give you pretty much the precise answer on what it is. My TJ was having the similar problem, and I replaced TPS, CPS, distributor rotor, serpentine belt and finally my sparks (which were the culprit from the beginning). Anywho, hopefully this helped. Goodluck!

 

[Bounty__Hunter]

My guess is IAC valve. I recommend removing your throttle body and all the sensors, then give the throttle body a good bench cleaning.

 

[josue estrada]

Mine was doing the same thing . IAC valve fixed the issue.

 

[JPNinPA]

Check for a leak near the TB or where the intake meets the head. Check at each cylinder. Use a can of starter fluid even WD40, spray around while idling and listen for the idle to change,.
Besides this then IAC or TPS as mentioned.

http://www.jeepforum.com/forum/f9/cleaning-iac-throttle-body-write-up-dummies-1114849/