My engine runs great on 5 cylinders... I went wheeling and drove it hard on the freeway for an hour and a half (3000 RPM) Had lots of fun wheeling for a couple of hours then had power steering problems and parked it for a couple of hours. When it was time to leave, I started it up and it ran perfect. Drove on some mountain roads at low speeds and low RPM to a gas station (20 miles). Put gas in the jeep and when I started it there was a loud rhythmic poping.
Here is what I think and have tried. I think the number 2 cylinder has a stuck intake valve. When I have the spark plug wire on and run the engine it pops everytime the number 2 cylinder fires (with no spark plug wire on it runs perfect on all 5 cylinders). At higher RPM (1500) the poping is really loud, and seems to disrupt the gas flow to the other cylinders. Sometimes the poping is powerful enough to come up through the carb. So, I think I have an intake valve stuck open or burned. I have run Auto trans fluid through the carb, I have changed the oil and run it with a mixture of oil and auto trans fluid. I have changed the oil and run it with an oil additive that is suppose to clean valves. Nothing has worked. I can look in the oil filler cap and see that valve going up and down. The engine has 170,000 miles. Any ideas to unstuck the valve (if it is stuck). I guess if it is burned up, then I need a rebuild.
Thanks for the help.
82 CJ-7, dead 258, auto, 33's, 4.56 gears, detroit locker (rear) true trac (front)