Need help: Grand Cherokee running bad

Trevor · Aug 3, 2007

Jason is in Montana right now. 1995 Grand Cherokee with the 4.0L not running good. It will seem to run fine for a while, then it will start surging and generally running poor. If he slows down or stops, the motor will cough and stumble and barely run. He can rev it back up ok, but it will still surge. If he pulls over, turns the rig off, lets it sit for a little bit, it will run fine for a while. But it doesn't last long before it starts surging and running bad again. This rig does not have an inline fuel filter, it is part of the pump according the manual and Jeep dealer.

Does this maybe sound like the pump is taking a ****? Could it be a TPS? He just called and made it to Butte, Montana. He is having no luck finding someone with a scanner. He went to the Checker auto parts (Shucks), and they can't do it for some reason.

Any help would be great.

JayH · Aug 5, 2007

Cycle the ignition key on-off-on-off-on within three seconds and the Check Engine light will display any stored DTC's. 55 is the end code.

Trevor · Aug 5, 2007

Finally got it scanned. Found nothing. After a bunch of messing around finally figured out that the catalytic converter is plugged up.

crash2 · Aug 5, 2007

Trevor said:
Finally got it scanned. Found nothing. After a bunch of messing around finally figured out that the catalytic converter is plugged up.

whooops

Trevor · Aug 6, 2007

Jason found some farmer out in BFE that let him use his shop. Cut the cat open to find that a piece had broken off inside and was plugging the outlet. Emptied it out, welded it back together, and he is good to go now.

crash2 · Aug 6, 2007

Trevor said:
Jason found some farmer out in BFE that let him use his shop. Cut the cat open to find that a piece had broken off inside and was plugging the outlet. Emptied it out, welded it back together, and he is good to go now.

Did the same thing on the wifes blazer.

You can typically hear a certain noise the exhaist makes when you have a restricted cat. I will have to tell you a funny story about that some day trev....

GaryTJ · Aug 7, 2007

when you get that nasty rattle just off idle coming from under the vehicle, it is generally best not to ignore it. Jeeps are famous for the cats coming apart.