your fans coming on at start up is a computer problem
seen a 93 Z with the same problem and it runs like crap now it wont even start
i think it was the opti thats bad and some plugs and wires and the ecu is really screwed up but im not completely sure

 

Yeah, when I had a burnt thru spark plug wire it messed with my electronics a lot. Just one bad one made my heat/air not work, I could hear it try to flow, but nothing came out of the vents. So check those out, see if any are bad. That could be the source for all the electrical problems right there.

 

It could simply be the water temperature sensor on your driver side head.

We chased a problem on my friend's car for 6 months with all the same symptoms and that is what it turned out to be.

The sensor goes bad and the computer things the temperature is way off. It then pulls timing and adds a crap load of fuel.

His car would kind of crank up sometimes but then would die like 30 cats had pissed on the opti!

For a $2-$5 part and 2 minutes of work it couldn't hurt.

 

Shows how much the person above me knows.

The driver's side head sensor is only for your gauge cluster, the pcm does not know what it reads.

The pcm sensor is in the water pump housing.