I have read that the ideal idle would be more around 750rpm but if you read a bit on the matter, it seems that they are all over the place too...
My low idle was just at 500rpm and I had a rought idling, with lots of engine noises (possibly knocks).... after adjusting the idle, to 700-750 rpm, the noises disappeared and the engine seems to keep the idle more steady.... of course I did that AFTER I cleaned some sensors and vacuum line and didn't check in between.... (kind of stupid me being a scientist to change 2 parameters at a time but anyway)
By Frantic advice, I went and bent a little the small plate that is attached to the throttle cable and that rest on a non adjustable screw....

good luck on the rest of your quest, i am following your updates and technical discussion with great interest....

 

Labor Day Update

So I disassembled the t-body on Friday night. Took off the IAC, MAP, and TPS. Also took off the IAC housing, completely exposing all the openings to the t-body. Got a gallon plastic bottle, hacked it in half, then went to work on spraying down the t-body with Deep Creep. Wish I had a helper with camera as I would have taken pics of it all. The t-body was BLACK. I'm surprised the Jeep ran at all with how bad things were caked up.

Took a couple of rounds spraying, scrubbing with a tooth brush, spraying again....etc. End result was a very clean t-body.

So I cleaned the parts going back on as well (some Deep Creep on a paper towel and wiping down), assemled everything, and then started it up.

Noticeable differences were:

- better start up
- better idle
- no hesitation when giving gas
- no hesitation or funny idle after stopping at traffic lights
- no hot-start issues after long ride
- much better acceleration in all gears

So, I have about half tank of gas left. Once I refill, I'll be keeping tabs on miles to the tank.

CPS is being delivered tomorrow, so maybe I will hold off on installing that until I run through one full tank of gas tosee if there are any lingering issues.

Thanks for everyones' comments & suggestions. Hope to have more info to post so this thread can help other with the same issues.

 

good job....
well so in the end, you just cleaned right ? Have you changed other parts other than the CPS ?
if so, would you give a summary ? lol
like I did this and it did / did not change anything ? etc ?

and that should be a lesson for everyone of us of course... let's start by keeping the engine / parts clean lol

 

Nope....CPS is still in the box. Haven't changed it yet.

I'm gonna drop in a can of BG44K this weekend. My order arrived last night, so I'd like to see what this stuff does to completely smooth out my ride.

I have a list of items I'll be changing out in the next few weeks, so I'll try and document all those updates as well.

 

I had a similar problem with my '96 country 4.0L. The Jeep would stall without warning or codes. The fix is very simple. Repalce the fuel pump relay. $8 fix.

 

Update 9/13/10

Poured a can of BG44K in about half a tank of regular (87). Only drove 1 mile to the doc this afternoon and back, so will have to see tomorrow how things feel on the commute to work.

Stay tuned......