OK i have a 93 yj 4.0 and now this thing is not letting me rev pass 3000 rpm but idles perfect.
Today as i was going home from work. i notice my jeep started to bogg. i got home and in the drive way i was trying to let it rev pass 3000 but she spudder's. i then add a fuel injector cleaner and let the car cool down. went to the gas station with no problems as i was going home same thing. so i decided to check the ignition (i just did a tune up a month ago when i first got the veichle) i hook up my timing light to each wire and the thing is lighting perfecly. so could this possible be my fuel pump but why would it only do it when the car warms up. i'm not to sure the temp also because when i got the vehicle the temp sensor is not there.

thanks for any ideas
lee

Ia there a fuel filter on that Jeep? Sounds like a mostly stopped up filter don't it.
Big Jim <img src="/forums/images/graemlins/pfft.gif" alt="" />

this morning checked the fuel filter no clogs. and today i'll be replacing the fuel pump and filter with new ones. so if the problem is still present any idea on what it may be?
thanks
lee

PLEASE replace the filter first and then drive her!!! Only after that not repairing it should you attempt any other repair.
You could be having a worn out tune on the engine... Did you replace the coil? Wires?
Big JIm <img src="/forums/images/graemlins/pfft.gif" alt="" />

thanks for the help turned out it was my cat converter. The damn thing was falling apart inside. the way i found out was i removed my o2 sensor to get a replacement. after i took it out i started it up and the thing revved up, drive down the street with no problems. then i put the sensor back in and back to it's old self.
so i had and extra cat and muffler from a 99 xj. after some welding and cutting i've finally got to feel the power of my 4.0 for the first time. again thanks for help
lee

<img src="/forums/images/graemlins/smile.gif" alt="" /> Ususally when them things get stopped up the tail pipe WHISTLES.. GM had a problem with the way they made the crossover pipes waaaay back in the 80's and the damn things CLOSED up under extended heat. Guys would start out for California with their new car and get bout maybe 500 miles before the thing started slowing down.. They would wind up doing 30 on the highway with the pedal on the floor..
You had bout the same problem with that cat.
Big JIm <img src="/forums/images/graemlins/pfft.gif" alt="" />