Maybe a dumb question, but thinking I need to replace mine. The jeep starts and runs great but every now and then it will loose all power for a second or two while driving.

 

i would check a fuel filter first. if your aint done one the put a new one one. its only a few bucks and cant hurt.

 

Yeah, thats what I was gonna do before the replacement. Im gonna get that done today!! Thanks!

 

My 94 would lose power when stepping on the pedal when pulling out , or climbing a grade and sometimes just running down the freeway. turned out to be the TPS.

 

Hey Mike Mike! Did you just have to replace the sensor?

 

Turn the key over but dont allow it to start. You will hear it cycle [ buzz] on the ds behind back wheel.

 

He's right see if you can hear the buzzing noise. Sometimes it's easier to have someone put their ear to the gas tank. Take off the fuel cap and have someone put their ear to the line and turn the key to the on position dont start it and see if you hear a buzzing noise. If not try to switch the relays on the AC relay or another one just to see if you hear the buzzing after that, if not then your pump is most likely out

 

Just because you can hear your fuel pump does not mean it is working properly.

Get a hold of an fuel pressure gauge and connect it to the schrader valve on your fuel rail. With the ignition on and the engine off the pressure should be 60psi. Once the vehicle is started the fuel pressure should be roughly 31psi. With the vehicle running disconnect the vacuum line from the fuel pressure regulator and cover the vacuum line with your finger. You should see a rise in fuel pressure around 9psi.

If you do not have around 60psi to then your pump is bad.
If you have 60psi with the engine off but dont make around 31psi than you probably have a blockage (fuel filter or in the tank).
If everything checks out but you do not see a change in pressure with the regulator disconnected than it is your regulator.

Alternatively it could be a bad injector or tps fault. Testing your fuel system dosent cost you anything. Replacing sensors gets spendy quick and it my or may not fix the problem.

With that said if you want to test your tps there is a simple method. Get a reliable VOM (volt ohm meter). Locate your tps wires (on later xjs there are only three on my 87 there are six). Ground the negative leed on your vom. with your ignition on and engine off take you positive leed and test each wire until you find about .5 volts (not the 12v feed). The .5v output is the signal to your ecu (engine control unit). The higher the voltage output the further open your throttle. With your VOM still connected to your tps output very slowly open your throttle. If you see anything but a smooth transition (increase in voltage) while moving your tps twords wide open throttle (3.9v+)than most likely your tps is bad.