8Mud
NAXJA Forum User
- Location
- Central Germany
Just throwing this out there, but many of the vacuum lines hook up to one end or the other on the intake manifold. The cylinders on the end with the vacuum leak run lean, the O2 sensor tries to compensate and the others run rich. This can cause hunting at idle, your motor doesn't seem to be able to find a steady idle as the ECU tries to compensate for the vacuum leak..
Check your intake/exhaust bolts for tightness, re torque. Torque the end studs very carefully, they snap off easy. I either leave the end studs or torque them to 15 Ft Pounds. I retorque my intakes at least every other year and always find something loose.
I always fill up the tank with premium fuel, do a tuneup, add a can of injector cleaner, put in a new O2 sensor and make sure the air cleaner is fresh. and take it for a run up the interstate for twenty miles. We pay for the test (every two years) and get one free retest, costs around a hundred bucks.
You can usually read the plugs and tell what is happening, soot covered and your are too rich or idle/slow speed drive too much. Bone white or too clean (silver or bare metal, or blisters) and you are lean. You get white plugs on one end of the block and sooty plugs on the other, likely a vacuum leak. After a long steady run up the interstate, you may have white plugs, doesn't mean much, my XJ's tend to run a touch lean near peak torque and steady pedal.
Check your intake/exhaust bolts for tightness, re torque. Torque the end studs very carefully, they snap off easy. I either leave the end studs or torque them to 15 Ft Pounds. I retorque my intakes at least every other year and always find something loose.
I always fill up the tank with premium fuel, do a tuneup, add a can of injector cleaner, put in a new O2 sensor and make sure the air cleaner is fresh. and take it for a run up the interstate for twenty miles. We pay for the test (every two years) and get one free retest, costs around a hundred bucks.
You can usually read the plugs and tell what is happening, soot covered and your are too rich or idle/slow speed drive too much. Bone white or too clean (silver or bare metal, or blisters) and you are lean. You get white plugs on one end of the block and sooty plugs on the other, likely a vacuum leak. After a long steady run up the interstate, you may have white plugs, doesn't mean much, my XJ's tend to run a touch lean near peak torque and steady pedal.
