'87 Cherokee extended crank when cold

Hey guys, I got this '87 Cherokee, 4.0L with A/T, a few months ago and have been doing some work to it, as well as using it as my daily driver.

It runs real well with 168K original miles on it, but it seems to crank for a long time before it kicks over, when it's cold. Once it's warm it fires right up no problem. I timed it out the other day and it will crank for 3 or 4 seconds when cold, before starting. That doesn't sound like a long time, but look at your watch and picture cranking while that second hand is ticking away for 4 seconds, it's long. Most cars, even older ones will start within 1/2 to 1 second of cranking.

I also noticed that when I first start it up in the morning, if I turn the ignition on and let it sit on for about 20 seconds, it will start much better, but it will crank, then half kick over and then finally fully kick over, but does it faster than when I don't leave the ignition on first. Any idea or known causes of hard starts on these 4.0's?

Also, and I don't know if these two problems are related, but it tends to idle rough at times but other times it will idle smooth as can be. When it does idle rough, RPM sounds like it drops real low (no tach) and it sounds almost like a miss, but then it will just kick itself right back up after a second to normal idle speed. It never stalls, just hunts around. It almost sounds like when you have the A/C on, and the compressor kicks on and off. Except it idles real low at times, sounds like it could stall, and will run rough for that second, then smooth right out. This is always worse when it's cold too. Once it's warm it will still do it slightly, but not as bad and most times idles pretty smooth.

I've read a lot on here about the TPS and IAC on this engine, and will check both, but what do I look for with the IAC? I know how to check the TPS, but what am I looking for as a problem with an IAC, just dirty?

Thanks for any help, Mike.

*Bump*- for a good description of the issue(s).. .
Sry, haven't the time atm...

But yeah, IAC can just be plain nasty. Take it off, clean w/ some carb or such cleaner, see what happens. If it were dead, you'd stall constantly...

Hit the throttle body while you're at it.

Long crank... check fuel pressure at the fuel rail.

*If you don't have this link already
http://www.lunghd.com/Tech_Articles/Engine/Basic_Sensors_Diagnostics.htm

**Scroll all the way down. '88 is pretty close 'eh?
http://www.lunghd.com/Downloads_and_Links/FSM.htm


Also read... lots 'o good info, even if not specifically your issue.
http://www.automotiveforums.com/vbulletin/showthread.php?t=687635

~Good Luck!