I bought a car with an Accel coil put inplace of the factory coil and lost my tach and the majority of engine power, but it still ran... barely

Swapped back to OEM coil and tach works and some power is back

Knock sensor code is tripped, the pigtail is fried.

Now for the questions

Can a poorly wired coil kill engine power but still allow it to run?
Im wondering why a cheap OEM out performs an aftermarket

Or was the power loss from the computers inability to know the engine speed?

Does the knock sensor code cause the computer to remove engine power in a last ditch effort to save itself?

The engine doesnt rev over 3500 RPMs even in WOT
At 3500 the engine will bog and the trans will shift and wind out again
Runs pretty strong up to 3500 but not at full power

Any ideers? I still havent fixed the knocksensor, waiting on a new pigtail