idle problem??????

[jasonjeepyj]

at idle my 95 YJ 4.0 will drop down to 400 or 500 rpm then spike up to 1000 or 1200 or so then back down to normal idle range. it will do this almost every 30 sec. and when the vehicle is warmed up and off. when i try to start it again she will not turn over all the way. she will crank and hit the spot where it will normaly turn over but instead she will bog a little and i will have to feather the throttle to get it to turn over and run. i am thinking it is on or more of the following; MAT sensor, CTS, TPS, or the AIS motor on the throttle body. any segetions? I have changed the fuel pressure reg. and i put in a brand new fuel pump and filter. i am almost sure it is a sensor. i want a second opinion.

[GP4Play]

What kind of carb do'es it have?My 84' CJ7 has the Carter BBD,that has the stupid step motor on the back,and I had to do what they call a Nutter by-pass to get my idel back.

[jasonjeepyj]

its fuel injected

[Jacob]

Search for vacuum leaks. Start spraying ether/starting fluid around under the hood while it is idling. When it spikes at a spot where you sprayed, look for and find the leak.

[mrclean]

I'd be looking at the Idle Air Control valve.......possibly gunked up and getting lazy, or on it's way to failure.

[JoeySnow70]

I'd be looking at the Idle Air Control valve.......possibly gunked up and getting lazy, or on it's way to failure.

Second that.... Take it apart and clean it with carb cleaner, I had same situation and was the AIC sticking because of cabon gunk build up.... A bad sensor should give you an CEL.....

[jasonjeepyj]

hey thanks alot guys, i will take a look at the idle control valve. i was thinking the same thing. i cleaned out the throttle body about 2 or 3 months ago. there was a lot of carbon in there. i did check the ICV. it was dirty. i will replace it and let u know. thanks Again.