I have a 93 Cherokee Country Auto with a 4.0 HO.
Here recently in the morning when she is cold she will hesitate thru out acceleration and at driving range. I am not sure if it would be considered a misfire, but you can see the tack fluctuate and you can also feel that it looses power for a second or two. She will do this even after she has warmed up to operating temp. But when I get in the Jeep after work and drive it home, it drives fine? Maybe it will do it once or twice.

She has a rebuilt engine (over 600 miles on her) and the plugs are pretty new. We are going to replace the cap and rotor tonight and see if that could be a problem (it needs to be replaced anyways).

Also she has died on me a few times. Not while I am moving, but when I am going into reverse and go to shift to drive or just sitting there.

Any ideas???

Plugs, wires, coil, 02 sensor or any other sensor?

Thanks Guys!

 

does it feel like the motor isnt supplying power or is the transmission slipping if its the transmision try checking the fluid as for the motor maybe the tps try cleaning it

 

The only thing that comes to my little Jeep mind is a bad fuel filter with the bad acceleration thing, but you may of just replaced while you redid your Jeep.

 

It doesnt feel like the transmission is slipping. Also if it was the transmission slipping the tac would not fluctuate, right?

As for the fuel filter, it has not been replaced. Can this really be a possibility?

 

If yhe trans were slipping the tac would fluctuate

 

We had a diesel Jetta that was a dog when the filter needed replaced. We took it in and after they were done, my dad let me drive it home and I felt like I was in a corvette (well, not really). But yea, the mileage went back up to the 47.5 and it gained all its torque... I really miss that little car...


btw when the car accelerated, the gas pedal would shake, which was weird because the car wasnt old. As soon as that was fixed, it stopped...

 

If the trans were slipping would it only slip shifting thru the gears? Or thru out the whole driving range? And would there be any indication this is thr problem seeig how it only does it mostly in the mornings when it is cooler and not when it is warmer out?

I really do not think it is the trans. It really feels like it is the motor. My car used to do this, but it was alot worse and it turned out the be the computer malfunctioning. But the Jeep isnt doing it as bad, so I am hoping it is something simple like a sensor?

Any other ideas?

If it is a fuel filter, I am only getting around 12 mpg. But it is lifted and has 31's on it. Maybe that could be an isue?

 

I wouldn't think it would be the trans either, the AW4 is pretty bullet proof. It sound like a TPS or fuel filter.

 

12 seems a little low, IMO

 

What does IMO mean? Or is that anything?

Is the fuel filter easy to get to on these Jeeps? Where is it located - In the engine compartment or under the body?


Is there anyway to test the TPS?

 

In my opinion...

There are still a couple that I dont know either

(and I still dont know what imao means)

oh, and it should be easy. My dads '87 mj has it right on the inside of the frame rail on the drivers side I believe. You cant miss it. Just looks like a cylinder about 3 inches in diameter. Took about 10 minutes to replace. Took more effort to open the box.. LOL

 

the fuel filter is an easy change its back near your fuel tank just bleed the pressure off then disconect the fuel lines from the filter and and pop in the new one even if it isnt your problem its a goo idea to change it and it only costs a few bucks there is a way to test the tps i will se if i can find the writeup in one of ny folders here it is

THROTTLE POSITION SENSOR (TPS)
1) Turn ignition on. Check throttle position sensor input
voltage. Connect voltmeter negative lead to terminal "B" (M/T), or
terminal "D" (A/T) of sensor connector. Connect voltmeter positive
lead to terminal "C" (M/T), or terminal "A" (A/T) of sensor connector.
NOTE: On (A/T) models, connector terminals are identified by
letters molded into back of connector. On all models, do not
disconnect TPS harness connector. Insert voltmeter test
leads through back of wire harness connector. On some
models, it may be necessary to remove throttle body from
intake manifold to gain access to sensor wire harness.
2) Move and hold throttle plate at wide open throttle
position (M/T), or close throttle plate completely (A/T). Ensure
throttle linkage contacts stop. Note voltmeter reading. Input voltage
at terminals "B" and "C" (M/T), or terminals "A" and "D" (A/T) should
be 5 volts.
3) Return throttle plate to closed throttle position (M/T),
or maintain throttle plate in closed position (A/T). Check sensor
output voltage. To do so, disconnect voltmeter positive lead from
terminal "C" and connect it to terminal "A" (top) of sensor (M/T), or
from terminal "A" and connect it to terminal "B" (A/T).
4) Move and hold throttle plate in wide open throttle
position (M/T), or maintain throttle plate in closed position (A/T).
Ensure throttle linkage contacts stop. Note voltmeter reading. Output
voltage should be 4.6-4.7 volts (M/T), or .2 volt (A/T).
5) If output voltage is incorrect, loosen bottom sensor
retaining screw and pivot sensor in adjustment slot for a coarse
adjustment. Loosen top sensor retaining screw for fine adjustments.

 

Well i will start by replacing the fuel filer along with my cap and rotor tonight. We are also going to pull the plugs and see if any of them are burnt up or anything.

As for testing the TPS... that sounds pretty intense!
But thanks for the info! Maybe it will make more sence to my hubby then it does to me.

Any other ideas guys? Any will help!

Thanks!

 

its not that hard of a procedure really if your jeep has high miles and the tps is original it might be a good idea to replace it but the testing is easy just gotta read through it and take it step by step

 

Well before I rebuilt the engine, she only had 116,000 miles on her. But I know they were hard miles (ie- i had to rebuild the engine!)

So maybe I will just replace it and see if it helps, I found one for $35. So it isnt too expensive.

Ill narrow it down before that. If its not the cap and rotor or the fuel filter, then we will start with plugs and wires, then an O2 sensor... If those dont fix it, we will try the tps.

Thanks!