Yikes, you don't mention a Check Engine light, but if the timing is so far off that you're turning the exhaust manifold red, surely it's throwing codes. Retarded timing makes me think of the knock sensor.

My own regina car had frequent CEL's and lackluster performance due to dirty contacts in the wiring harness that were causing the computer to get an imperfect signal from the knock sensor. Cleaned the contacts in the big multiplugs that are clipped to the drivers side strut tower support and there have been no probs since.

John