Still having a problem!

In my last post i found a bad ground connection which ive replaced in my Renix 90. But my original problem is still occurring. It keeps stalling. Not all the time just seldom but enough to drive me insane. Tonight I was at a friends house just hanging out. I asked his father about my problem and he told me to adjust my idle screw a little, so I did and it brought the idle up to a round 700 rpm while in park. I turned it off and went inside. Came back out and started it and it ran like CRAP! Missing and running rough and spewing an abnormal amount of exhaust out of the tail pipe. So I reved the engine a few times and thats when the engine stalled almost like it was choking itself. It started rite up again but still running like crap. Finally after about 5 minutes of running like crap it got warm and smoothed out. Can anyone point me in the right direction as to what might be causing it to do this. I know Im probrably !!!1 with this but Ive just gone through the last 50 pages of this forum looking for anything that might help. Thanx in advance.

~MATT

I didn't read through your other post, so I don't know exactly what you've already checked. But the crank position sensor can be a sometimes thing, often associated with temperature. It will usually test to the outer ohm range specs when cold or hot, then the ohms may change with the temperature. In other words the CPS can get really iffy, best to do an ohm test, clean the connector and check to see if the wires are frying on the exhaust manifold.
EGR valve hanging open or the EGR solenoid loosing power (the connector gets brittle and breaks) the solenoid is default open and will keep the EGR open at idle if the power is interuppted, which makes the motor stall and run poorly at low RPM`s. EGR, open or closed, has little affect at higher RPM's, that are noticeable.
TPS grounds or a bad TPS can cause grief and make your idle hunt, sometimes too low, sometimes too high. If you have an auto trans, there are two grounds coming from the TPS, that run by different paths to the same place and eventually end up at the engine dipstick tube brace.
The vacuum line to the MAP can cause it too run really rich.
The IAC can be sticky, or your general voltage can be too low for whatever reason. A bad battery or low charging can affect IAC function noticeably. The IAC seems to need every volt it can get to function properly.
I had one 87 that was stalling and running poorly, turned out to be the fuel rail harness where it runs down the front of the motor to the O2 sensor, the engine temo sensor and the knock sensor was cooking on the exhaust manifold. It was hard to see, I actually had to crawl underneath with a flashlight. I starting checking other XJ's after that and found a bunch over the years, that had the same thing going on.
A few things to look at.

Don't mess with the idle screw. Have you tried simply cleaning the throttle body and idle control passage in there? 8Mud has some good suggestions there too.

been down that road a ton of times! I just replaced the TPS and CPS on sunday. Took the throttle body out cleaned it replaced the gasket and cleaned it again. As of recent it has also gotten a new O2 sensor with say 3 weeks and also fixed a couple of vacuum leaks.

Did you change out the TPS or did you have someone do it. Did they/you adjust it properly. The CPS connector could still be messing with it. I have read where people have changed out the CPS only to find it was the opposite connector the CPS plugs into was corroded. Something to consider.