On my 95 cherokee with 240000 miles, I started it up about a week ago and the RPM's jumped to 1800 and stayed there unit I shut it off. After that it was normal until this morning and it jumped to 2000 and stayed there. Any ideas?

 

You can clean the IAC. (idle air control), on the TB. Mine turns out was actually the wiring plug on the IAT. I'm thinking since the socket points up, on my 90, there is a better chance for moisture to get in there.

Less likely...It might be on my 90 the "power latch" relay, provides power for a few seconds on shutdown for the puter to reset the IAC for the next start. 94 may well have something similar. I suppose it's unlikely that's an issue.

Btw the "Key Trick" may well work on your 94 to read codes>

OBD1 Models: 1991-1995
1) Start engine (if possible). Move transmission shift lever
through all positions, ending in Park. Turn A/C switch on and then off
(if equipped).
2) Turn engine off. Without starting engine again, turn
ignition on, off, on, off and on within 5 seconds. Record 2-digit
fault codes as displayed by flashing MIL.
3) For example, fault code 23 is displayed as flash, flash,
4-second pause, flash, flash, flash. After a slightly longer pause,
other codes stored are displayed in numerical order. When MIL begins
to flash fault codes, it cannot be stopped. Start over if count is
lost. Code 55 indicates end of fault code display.

 

just a thought. Perhaps a vacuum leak from the manifold gasket?

 

It doesn't do it if the break is depressed.