the_mumbling_jeep

jeep takes awhile to crank when its cold outside. before jeep fully warms up when I'm at dead stops and press gas pedal the RPMs drop to near 0 or it just flat out stalls (its automatic) and when doing between 40-60 the rpms will bounce around and feels like its jerking. i replaced TPS, CPS, battery, cleaned throttle body, replaced air filter, replaced whole distributor. Any ideas feel like chasing a ghost.

Jeepin'Hubb's

Need to check fuel pressure to see how that system is operating as well. Erratic pressures can cause your symptoms.

1arunem

how old is fuel filter?

the_mumbling_jeep

fuel filter/pump is only about 2 years old

RTorrez1

Start by checking you fuel pressure at the fuel rail. It should be 49psi. That is if you are talking about the 98 on you profile??? You need to always put in you post the year. model and engine size. A lot of people won't give you the time of day if you don't give any details on you vehicle. Also make sure that you have a strong blue spark.

Jeepin'Hubb's

I've had a new pump fail within a few months. Check fuel pressure at the rail just to rule out that possibility.

RTorrez1

What brand of pump did you put in? Also just because a part is new doesn't mean it can't be bad.

Jeepin'Hubb's

I don't remember, whatever advance auto sold at the time. I don't buy parts from them anymore...not just because of that, also because the employees they hire at my local store know jack squat about anything.

tjwalker

This. Especially if it is an Airtex fuel pump.

Gotta test fuel pressure with a gauge, which often can be rented for free or inexpensively from many parts stores; call around.

The fuel pressure spec. for the 98 is 49 psi, plus or minus 5 psi.

Let data drive the bus here. Test your way to a solution. And of course if there is a check engine light, retrieve codes for guidance.

Don't forget about the condition of all tuneup parts. Plugs, wires, (you replaced cap and rotor with new distributor).

Jeepin'Hubb's

like i said already!!!

RTorrez1

What kind of pressure are you getting? Is the pressure holding or does it drop off? If you want help you have to let us know what's going on. We can't just guess what the pressures are. If you checked it did you use a mechanical pressure gauge or did you just push the valve to see if it had pressure?

BimmerJeeper

This list might help
https://www.cherokeeforum.com/f59/to...h-idle-155383/

Jeepin'Hubb's

I think you got me confused with the OP my jeeps runnin fine...

the_mumbling_jeep

im not sure what pump was replaced with i just know the old guy who had the jeep before me had it replaced right before i bought it so not sure what brand the shop used. going to test fuel pressure tomorrow at my friends shop he's going to do it in his free time for me. if its not that it then going to look at injectors which i was told could be it to. the check engine light isn't giving anything off besides bad rear 02 sensor which happens every time it gets wet from rain, snow or anything.

DFlintstone

I don't have much to say with TJ and Rt here. The Not platinum plugs, are gaped to .035, (a given?). I assume it cranks fine, but doesn't fire up. If it fires faster when you hold it on the floor than it does when you don't, that might be a clew to someone. It might cut off fuel when floored. (then it would fire faster then it would if it waz flooding). I'd check the codes if mine had that. Multiple misfire from vacuum leaks?
Tell them about the idle.