Started the jeep in the morning with no problem. Parked it for a while came back started it no problem again. But after starting, it had like a misfire where the rpms dropped and bounced back up to normal. Parked it again and now it doesn't want to start. All it does is cranks but no start. Any input what's causing this. Thanks

 

Well I gave it another try went to start it and it was just cranking and I decided to hit the gas pedal a couple of times and bam it started. Went around the block got back home parked it. Went to started again and just cranks.

 

If it starts when you press the gas pedal, I'd guess that it's the TPS. I'd grab your meter and check it.

 

It starts now but once it gets close to operating temperature it starts misfiring, rpms go crazy and after a little while it shuts off.

Is there another way to test a fuel pump to see if it's good or not other than through the ignition?

 

When you get it running take it to the parts store and have it checked for any codes even if you don't have a CEL coming on, You can still have stored codes. Also Yes you can have a pressure test on the fuel rail. When you take it in to have the codes read see if they have a mechanical pressure gauge and hook it up to the fuel rail. For your 99 you should have 49psi +or- 5psi. But it does sound like a TPS problem like scottmphoto mentioned.

 

I don't want to risk getting it stuck on the road. I'm just going to rent the scanner. I had unplugged the battery and no CEL. once I would start it and it got to the point of turning off the CEL always comes on.

 

These are the 3 codes it gave me.

 

Fixed. Ended up throwing on another crank sensor and a pick up coil and everything is good now.

 

Checking for codes is always a good place to start and can lead you to your problem. Glad you had them check and got her going.