99 Cherokee Sport won't start

[MauiJohn]

When I drive my car every 1-2 days I have no problems. When it sits for about 4 days it will not start without me pushing the gas pedal to the floor first as I turn the key...........then it will start, but I have to continue to give it gas for a few minutes so it will not cut off. Once I drive it for a couple miles it will run fine and start everytime, as long as I drive it everyday or so.

Earlier in the week I had the battery tested. It needed to be replaced, but this has not fixed the aforementioned problem. The starter and alternator seem to be doing their job. This is otherwise a strong running vehicle. Oh, I had also added some fuel injector cleaner to the gas this last time, but this has not helped with the problem.

Vehicle has about 100,000 miles.

Any ideas?

[wwwildman]

I would start with a fuel pressure test. It should be 31 psi while running and 39 psa with the vacuum line disconnected. It could possibly be the fuel pressure, the pressure regulator, and/or fuel pump.

[AlohaBra]

Pressure drop in the fuel rail while sitting is a common occurance.

See some of the other posts on this.

[MauiJohn]

Thanks for ideas. I was thinking something along those lines from what I have researched. It's good to know there is some good information coming back on this site. Your information lets me know I may be on the right track. I have someone looking at it for me trying to diagnose the problem. This may take sometime since the vehicle will need to sit for several days so the problem can be recreated for troubleshooting. I will post the final findings for others.

Thanks.

[AlohaBra]

I would not worry about it, if you use this technique to start the vehicle.

1. Turn the key on and listen for the fuel pump in the rear
2. Turn key back off, turn off AC switch (if it is on)
3. Turn the key back on and wait a couple of seconds
4. Then crank the engine

If this doesn't work, looking into replacing the crank position sensor.
BTW, check for battery voltage after sitting for four days, it could be weak.

[MauiJohn]

Ok gentlemen, here are the findings. The IAC was way off the charts on start up and the air throttle was full of dirt and junk. The IAC was replaced and the air throttle was cleaned. So far so good. She is starting and starting stronger than ever before. I hope this is a fix to the problem. If anything changes I will advise. Thank you all.