1999 won't start, idle air intake problem

I joined this group in hopes someone could help me with a rather puzzling problem I am having. My Cherokee won't start unless I hold down the gas pedal and then slowly let off the gas. The problem is intermittant, although it has become much more prevalent over the past month or so. After taking the air intake hose off the vehicle, I noticed that the idle air intake valve was not opening on ignition. So I replaced the idle air intake valve, but still have the same problem. I also replaced the throttle position sensor, again with no luck. I have checked the fuel injection valves, and there are no leakes, and nothing appears to be gumming up the air intake. All the hoses are in good shape, and I can't find a sign of leaking anywhere. At this point I am not sure what else to check. Any ideas?

Thanks in advance,
Chris

maby its your computer it may need to be reprogramed. not sure if this is the problem but its a start.

I do not have any experience mucking with the computer software on vehicles, although airplanes is another story... :) Is there any way to do this without taking it to a dealer and having them take me to the cleaners? I had kicked the idea around of a faulty computer, but since it is intermittant, and only on engine start, I did not think it could be at fault. On the other hand Sherlock Holmes was often right (eliminate all possibilites and what is left must be the solution)... Is there anything else that it could be, that I could be missing?

Thanks,
Chris

have you had the computer read. meaning the trouble codes that the computer stores when something goes wrong. you can buy a code reader, and get the codes off the computer your self. go to any automotive store like jegs and see if they carry a code reader for your jeep. this maybe another avenue for you.

also check your fuel pump and regulator the fuel pump maybe not producing the right pressure. or the regulator has faild. you can buy a fuel pressure check tool from any automotive tool store. hope this gets you closer to the problem.

Well I fixed my problem over the weekend. It turns out that when I replaced the battery (I was still using the origional battery from Chrysler), it starts just fine. The battery was getting old, but not showing any problems turning the engine over, etc. but it looks like it was just weak enough to muck up the eletrical system.