eddera

i have a problem with my 2000 jeep cherokee that i can't figure out...two days ago it would crank but it wouldn't start. if i give it gas it'll start but unless i hold the gas pedal down some the rpm's just drop till it cuts off. after it's been running for 15-25 minutes it'll idle like normal. other than that it runs just as good as ever. i've disconnected and reconnected the battery, cleaned the iac valve and my tps is displaying correct voltage. also i do NOT have a check engine light on...i'm lost and would appreciate any ideas

thanks,
jake

eddera

just a btw it's a 4.0 if that helps, thanks

fughley

I am having the exact same problem with mine!
Make any progress?
It seems like it either catches and fires up fine or I miss the first cylinder firing and it just wont start unless I give it gas. I checked all the vaccum fittings and didn't find a thing.
I'll keep watching this thread.

trans_am7935

the TPS (throttle position sensor) could read voltage, doesn't mean it is functioning. i would replace that, but first look for a vacuum leak. check for a cut in your brake booster line or on the vacuum line from the throttle body to the map sensor. a bad TPS sensor will not throw a code unless it is broken. a malfunction will inconveniently not throw a code. unplug the TPS sensor and see if it does the same thing, or if the check engine light comes on.good luck

eddera

alright i know all my lines are good but i'll check the tps in the morning and just for overkill i'll probably check my cps, egr, check my intake for a leak and have autozone check my battery...hopefully that takes care of the problem haha

jsport

i had almost the same problem with my old jeep it was a piece on the fuel pump i forget the name but i just turned my key to on and off about 4 times then started rite up

trans_am7935

i believe you are talking about the sending unit on top of the fuel pump, it is the piece that tells the fuel pump to turn on when the ignition is in the on position while the engine is still off. after that the constant voltage from the computer tells it to keep running.

eddera

yeah mine was just the battery...

fughley

OK I just replaced the TPS and no change in condition.
And that was after pulling the harness off of the sensor as was mentioned earlier. So The sending unit could also be a problem?
On to the next possibility.
Eddera- I noticed that you mentioned that the battery was the issue, how so?
I replaced my battery cables and the starter power circuit with 1 gauge cable. I wonder if that could be a factor......
Thanks for the input and if i get this figured out, I will post it.

Diesel

Check for constant fuel/spark.