All,
Thanks to Bill & Mike for the help last time. This is getting silly. I replaced the fuel injector, and the problem changed. At first, everything was fine. After running it for a while (~20 minutes), it developed another problem. If I'm not in gear, the engine runs smooth, no matter if I rev the engine up or just let it idle. The moment I try to move forward (it's a manual), the engine sounds like it's missing on a cylinder again. But if drive in reverse, the problem doesn't occur.
Again, this is an '82 Scrambler with the Mopar fuel injection kit. I know there's a sensor that tells the CPU whether or not the Jeep is moving. This seems to tie it to the speed sensor somehow, as I don't think the speedometer cable (and hence the speed sensor) turn when in reverse.
I don't think I got a bad injector, as it works fine in all conditions but going forward. I don't think the speed sensor went out on me, because it seems to me that the engine would run just like it did while in reverse. Is the CPU partially dead? I tried power cycling it, but that had no effect - maybe a trip to the bone yard is in order. I guess I should check for pinched wires or a bad ground. I don't want to drive it much, because if it's the computer, it could fry the injector again. Or maybe this is the occasion I borrow the oscilloscope from work :).
As you can tell, I'm still trying to figure this out. Any help would be greatly appreciated. Thanks in advance.