I have a 1986 240 wagon that has twice exhibited some strange symptoms. It had an extreme lack of power on acceleration, backfiring when letting off the gas, and a very loud noise that sounded like an exhaust leak in the front. Both times I drove only a short distance (a few miles) and upon pulling over my exhaust manifold was glowing bright red. (We have ruled our problems with the cat converter). I have been told that the engine is likely running too lean, and it does seem to be a fuel related problem. At all other times the car has run relatively normally although it does run a little rough and you can often feel tiny cut outs as you drive, although the engine has lots of power.
Car is not a turbo.
Ideas?