Help Diagnose Issue - No Trouble Code

Here's the deal: The XJ (99 - 4.0 - AW4) will start, but will not stay running without throttle input. With throttle input it runs smoothly, but RPM's drop as soon as throttle input is removed. No trouble code was triggered.

Ideas?

maybe a tps i just had my tps unplugged earlyer and it was running real bad but it stayed run on its own but as soon as i gave it gas it would back fire through th intake but here is a web site that was given to me its purty good http://www.lunghd.com/Tech_Articles/Engine/Basic_Sensors_Diagnostics.htm\
hope it helps

My first incliniation was the TPS, but it would run fine if I kept the RPM's up.

IAC seemed most likely, so I cleaned out the throttle body and IAC inlet with electronics cleaner. The problem's gone (for now), but I bought a replacement at Auto Zone for around $45 that I'll put in and keep the old one as a spare. (BTW, $88 at NAPA and $107 at Murray's.)

Thanks for your ideas,

Tom