I've scanned threw the threads and couldn't find my specific issue so if I missed it I apologize in advance.


Ok so I have a 95 xj automatic obd1.the jeep will start great cold/hot and drive fine on backroads, highway,or wheeling threw muds and big rocks for a few hours but right after that few hour mark it will spudder and not allow me to give it more than about an 1/8th of throttle. Also hear like its backfiring in the intake manifold. I replaced the cps twice with two different brand sensors(thinking the issues was a faulty one the first time) and here's a list of whats been replaced withing 60miles

fuel pump with screen

Fuel filter

injectors

plugs

Distributor cap and rotor

Water pump and thermostat

Alternator

battery

Cleaned the air control valve

Oil change

Transmission filter and fluid

Radiator flush with new coolant

Jeep doesn't overheat with no check engine codes.checked the fuel pressure and its at 39 psi .but I did notice that last time i took it out it did drink some coolant from the reservoir. Im new to the thread so once again i apologize if there is another thread to my specific issue and any help would be greatly appreciated as I'm now stunted

 

An imbalance of fuel to air is my first thought. Fuel pressure for your 95 should be closer to 31 psi at idle. Then disconnect the vacuum line leading to the fuel pressure regulator under the hood and the pressure should then be closer to 39. As the regulator is inexpensive and very easily replaced, you might want to get a new one installed. If the vacuum line leading to the FPR has raw fuel in it, that is confirmation that the diaphragm in the regulator has ruptured. Also, the MAP sensor is directly involved with fuel/air ratio. They can be tested.

If it's burning coolant, that is a wildcard for sure. Keep very close tabs on the amount consumed. Comprehensive check for leaks including the seams of the radiator, a common spot for small leaks. If you need to add coolant, it's either leaking it or burning it. If consumption continue and no leaks, check compression as a blown head gasket is not out of the question here. The compression spec for the 4.0 engine is 120-150 psi with no more than a 30 psi variation between cylinders. The variation between cylinders is the thing to really look for.

Good luck and keep us updated!

 

sorry it is at 31 and 39 with the line off the regulator and no zero fuel behind the regulator