92 RS, 3.1.... The car will idle fine then all of a sudden it hesitates and becomes very rough and very sluggish. Its like im loosing half of the engines power, acceleration is very very poor, shifts harder and the tach just bounces around. Then sometimes it'll hestitate again and clear right up and run normal. Also, when its running rough the water temp increases above normal, nothing bad, but the gauge shows a difference.

 

Because of the bouncing tack, I would take a look at the coil packs and ignition module under them first. They tend to break down with age. Does the check engine lite come on when this happens? How is the voltage acting?

 

Ok. The voltage stays the same. Its up just above 13.
Would the coil pack do that to the engine? Sometimes she runs fine, then others its just a rough ride for 10 secs and then it clears. No engine light at all.

 

The ignition module, in particular, can get pretty flakey, especialle when it gets hot, and it also drives the tach. try taking the coils of and cleaning all connectors to the module, and remove and clean the big connector plugged into the module. Use spray contact cleaber fron Radio Shack. You can probably get the ignition module and the coils tested free at Auto Zone, or swap parts with a buddy. The other possibilty may be intermittent problems in the FI, like a sick pressure regulator, fuel pump, or injectors. May want to check the fuel pressure and pressure regulator with a FI pressure gauge, and check the wiring between injectors & PCM. Use NOID lites to verify the injectors are being fired while you wiggle the wires.