Nixt
NAXJA Forum User
- Location
- Plimmerton, New Zealand
OK, I'm at my wits' end here. Please help with suggestions and ideas.
1996 2-door XJ, 4.0, 5-speed manual. (~4" lift but still running little tires)
Problem:
Random rough running for the last 6 weeks- sometimes minor hiccups or hesitation, but at other times MAJOR rough running (obviously misfiring. No backfiring, though, just a "bogged-down" feeling to the engine most times. When it's really bad though, the shifter will literally shudder in my hand. Will happen most often at steady load in lower RPM range. But it also happens under acceleration, and at idle, just not as often as it does at steady speed.
What I've already done:
-Pulled codes from the computer: 300 and 306. Random misfires, and misfire cylinder 6.
-Plugs, wires, and coil were installed new 4 months ago (Bosch plugs, MSD other) Checked them first anyways, as well as my rotor and cap. Rotor was a bit dodgy, so I replaced the cap and rotor. All plugs when pulled look normal -grayish - not black not white. Strong spark when wires are pulled off and held near ground.
-Code 300 again.
-Fuel filter: replaced. Had some gunk in it that was weird, so I used an additive to kill the bacteria in the tank. (This was evidently not the cause of my issue, though. see my post here for more info http://www.naxja.org/forum/showthread.php?t=66781 )
-Code 300 again... (getting sick of this yet?)
-Fuel rail & injectors cleaned at a garage (hi pressure thingamabob)
-Again, same code 300, also 306 again.
-Fuel pressure is at 50 PSI steady, which is good. Check valve on the pump seems to be OK, too (bleed off test).
-Checked all ignition system ground points by eye and wiggle. They are fine. Checked misc other grounds the same way, none found bad. (Did find a bad connector on my headlamp lead, though.) No effect.
-Took it back to the mechanic, left it for the day with him. He pulled code 300 and 306 again. He tested a number of things, including the injectors for duration(? - or something) and I think the TPS. He didn't find anything in his poking around with it, and OF COURSE it didn't run rough while he had it. (Intermittentcy will kill me, i think...)
Now, oddly, I have had a few days of running OK. Still not perfect running, but I have had no notable rough patches. But, sure enough - this morning I had another rough running condition come and go.
Please, have mercy, and help me out with this. I am getting really worried that I will harm the engine by driving it around, but I don't have another vehicle.
Thanks...
1996 2-door XJ, 4.0, 5-speed manual. (~4" lift but still running little tires)
Problem:
Random rough running for the last 6 weeks- sometimes minor hiccups or hesitation, but at other times MAJOR rough running (obviously misfiring. No backfiring, though, just a "bogged-down" feeling to the engine most times. When it's really bad though, the shifter will literally shudder in my hand. Will happen most often at steady load in lower RPM range. But it also happens under acceleration, and at idle, just not as often as it does at steady speed.
What I've already done:
-Pulled codes from the computer: 300 and 306. Random misfires, and misfire cylinder 6.
-Plugs, wires, and coil were installed new 4 months ago (Bosch plugs, MSD other) Checked them first anyways, as well as my rotor and cap. Rotor was a bit dodgy, so I replaced the cap and rotor. All plugs when pulled look normal -grayish - not black not white. Strong spark when wires are pulled off and held near ground.
-Code 300 again.
-Fuel filter: replaced. Had some gunk in it that was weird, so I used an additive to kill the bacteria in the tank. (This was evidently not the cause of my issue, though. see my post here for more info http://www.naxja.org/forum/showthread.php?t=66781 )
-Code 300 again... (getting sick of this yet?)
-Fuel rail & injectors cleaned at a garage (hi pressure thingamabob)
-Again, same code 300, also 306 again.
-Fuel pressure is at 50 PSI steady, which is good. Check valve on the pump seems to be OK, too (bleed off test).
-Checked all ignition system ground points by eye and wiggle. They are fine. Checked misc other grounds the same way, none found bad. (Did find a bad connector on my headlamp lead, though.) No effect.
-Took it back to the mechanic, left it for the day with him. He pulled code 300 and 306 again. He tested a number of things, including the injectors for duration(? - or something) and I think the TPS. He didn't find anything in his poking around with it, and OF COURSE it didn't run rough while he had it. (Intermittentcy will kill me, i think...)
Now, oddly, I have had a few days of running OK. Still not perfect running, but I have had no notable rough patches. But, sure enough - this morning I had another rough running condition come and go.
Please, have mercy, and help me out with this. I am getting really worried that I will harm the engine by driving it around, but I don't have another vehicle.
Thanks...