jerodbailey

hello everyone, I have a 1997 Grand Cherokee TSI with a 4.0 6cyl and I have a laundry list of things I have done to try to fix my problems and was wondering if any of yall can shed some light on my situation.... My Jeep has had a problem that seems like it is not getting the fuel to the engine which is something like stumbling i suppose. Going down the highway it seems like someone flips a switch and it falls flat on its face. most of the time it doesn't die but sometimes it does. When the engine cuts out like that ad you stomp the gas it makes a loud backfire noise. Yesterday the muffler exploded which led me to replace it without the catalytic converter. I made sure and checked the sensor before removing the cat, and no check engine lights came on so i took it out and the problems still persist. I thought the cat may have been stopped up but there was nothing in it when i removed it. I have replaced the following items:
MAP sensor
Crankshaft Position Sensor twice
Ignition Coil twice
Fuel Pump
Muffler
Now this leads me to believe there is a problem that is electrical or there is a short in a connection somewhere. Any and all suggestions would be greatly appreciated. Thanks for your time,

Dumbfouned in Tennessee

tsconver

get a fuel pressure gauge and check your fuel pressure at teh injector rail to start out.

jerodbailey

That was one of the first things I did and the mechanic said that it was at a normal pressure.... just a hunch but would any of this be related to timing problems?

tsconver

is it a true backfire, that is combustion in the intake or is it an afterfire (combustion inthe exhaust)?

jerodbailey

I left this part out... sorry... When i said I replaced the muffler, that is because it literally exploded. It blew open at the seam. That makes me think it is a backfire in the exhaust but it would have to be in front of the muffler somewhere as I have removed the cat.