Claytony565

Hello everybody,

I wanna start out by saying thank you to everyone taking time to answer threads on this site. It has helped me tremendously in the past. I have searched many times for this particular problem I am having and I have yet to find anything like it, so here goes.

I own a 1997 XJ with the Country package, 4.0L 4X4. I have been having a few different issues recently. I have only owned the jeep for about 3 months now so I do not know much about service history. I have been getting three DTC codes consistently and they are
P0135 (Low voltage 02 heater circuit bank 1 sensor 1)
P0138 (high O2 circuit voltage bank 1 sensor 2)
P0301 (cylinder 1 misfire)I have done the following to the jeep:
New distributor, cap, and rotor
New plugs and wires
New O2 sensors (pre cat and after cat)
New fuel injectors (4 pintle upgrades)
New PCM
New IAC (idle air control valve)
cleaned up the throttle body and did the sea foam top end cleaner.

I am am having problems with a rough idle mostly. However, it has been losing power while I am driving but only once during my whole trip and it is always at the beginning. It does not matter if I am at operating temperature or not and it is not consistently before or after a shift. The only consistent part of this is it does it only one time, and at the beginning of my trip, typically when I am pulling out into a main road. I will say that last week it did throw a code for a transmission solenoid, but it has not thrown that again. When it loses power it just seems to be misfire randomly and there is a backfire and I can here it going in the opposite direction out towards the throttle body. I am extremely confused and I am trying to avoid a complete engine or transmission failure, any help will be greatly appreciated. I would also like to add that for the heater circuit, I have new sensors, from testing the circuit with a multimeter I don't believe I am getting power to the heater. If anybody knows which relay powers the O2 heater circuit that would be very helpful, I believe that is contributing to my rough idle. I need to know if I have continuity between the relay and my O2 sensor wiring harness. I also have an OBD2 scanner that I can access live data with if that helps. Thanks,

Clayton

tech

What it sounds like it could be losing fuel or your ing .coil is starting to go bad those 2 things can make it randomly backfire though the intake .

Claytony565

I was afraid of the losing fuel. I forgot to add that I just recently replaced the ignition coil. I'm going to have to take a closer look at my
distrobutor cap to see if it is in good shape. What kind of things should I start to look for when diagnosing the fuel issue? I think I've read somewhere that the O2 heaters are powered by the fuel pump relay, could lead to something but I'm pretty backwards on what is right and wrong at this point.

tech

The only way to check the fuel pump is with a fuel pressure gauge . you can replace the fuel pump relay to make sure that's good .

Claytony565

Well, my fuel pressure is good, falls between 40-50 and my relay tested 12V on the two positives. Could it be a fuel pressure regulator? Or maybe the purge line on the evap system.