Vincenza V

I have had a idle issue for about six plus months. I have an AW4 auto, 174K miles or so. My idle have sporadically gone to 1200 rpms and hands there. This occur with and without the AC on. It takes me hitting the gas pedal to get it to kick down. Being an auto, this obviously affects the downshift when slowing down to a stop.

Any ideas? I just took off the throttle body and cleaned it off the Jeep. I also cleaned the IAC.

DFlintstone

Maybe while it's high, push home on the throttle right at the TB. See if that brings it down...Btw mine turned out to be the connection/plug to the IAT. A really good cleaning there is what finally solved it.

Vincenza V

DFlinstone-You are saying to pop the hood, and press down on the TB arm or cable?

Roler

Might want to check for intake leaks with a carb cleaner spray.
Test the TPS.

Vincenza V

Good tip. I'll check it out. Thanks guys!

DFlintstone

Absolutely. If tapping the petal/linkage to the TB makes it settle down, the cable or something physical might be holding it up. Just go to the source and make sure it's "home". Sheez.... Do you work for the Government?

Vincenza V

Dflintstone-You got it right. I caught it at a parking lot in high idle and popped the hood. Pressed down on the TB linkage like you suggested and instantly calmed the idle down. Did it a few times just to be safe.

How hard are those cables to replace? One goes to the AW4?

I guess I can disconnect the TB side and try silicone first, see if that fixes it huh?

HappyTrails

Before you spend $$$ replacing cables and stuff, go back and make sure the throttle body and related stuff got cleaned properly. Right at the throttle plate shaft inside the throttle body is especially important. With the motor OFF open the throttle and spray cleaner and use a cloth rag to get it clean around the shaft above and below the throttle plate as best you can.

Also, check your return spring on the outside of the throttle body. Could be broken, weak, hung up etc. And check the cable routing, that nothing is pushing down on the cable in the wrong way.

And remove the idle air valve and clean thoroughly. Especially inside the hole once the plunger is removed. Its a bit hard to see, but a small mirror helps. Twist a small rag in there with lots of cleaner lots of times until it is reasonable clean. And clean the plunger real well before reinstalling. A dirty idle air valve often is the reason for the "rough idle" the 4.0l is supposedly known for. Amazing how smooth it runs when cleaned!

Sounds like your problem can be solved this effort and not money.

All the best.

DFlintstone

There's a "process" to "auto" do something to that TV cable. I like to just set it with about zero play. There's a button on top where the cable comes out. I just set mine maybe the thickness of a dime, or less from the nub on the end of the cable to where it pulls. I guess they are normally loose, but you should rule out that being tight, causing your high idle.

As far as the throttle cable, (and allot of other stuff), arisol "chain and cable lube", will darn near shoot across the street. The foam sticks where you shoot it, then as the bubbles burst grease is aplied to the..."target area". You can do your hood hinges at 10 paces! (and hit the petal end of the throttle cable as well as the other end and the linkage)

With the window down you can also shoot through the crack and hit your lock mechanism, window crank....even grease the window it's self! Spendy, but handy stuff.

Vincenza V

Happytrails-The idle is not rough, it just hangs at say 1200-1500 or so, every once in a while. I just lubed the spring/butterfly valve with silicone, and the cable ends. We'll see if that makes a difference.

Next step will be disconnect the cables at the TB end and hold them "up" while spraying down to see if I can get more lube down there.

DFlintstone

Sounds good. I've never heard of that tranny cable holding it open, but I suppose it could. You might take a shot at the pedal end, good luck!

Vincenza V

The superficial spraying I did didn't fix the issue. That means I'll pop the cables off and try saturating them that way.