well its not good that the Car will not communicate with the scantool....Did the dealer use the Tech2?

I've had my 95 SE SC refuse to communicate with scan tools since I used MOS95B'* Actron back in September -I've had a CE light off/on for the past month or so and even Tech II'* are like :?:

You never said if it happened under load. You said you replaced plugs, should do wires also. A bad wire or plug will feel like a tranny problem under load. The CE light will blink (meaning missfire), then come on steady. after a few starts and no other occurance it will go out automatically. My fuel pump took 1 year to die and I never suspected fuel pump till it finally did.

If your engine light is coming on, your PCM should have stored a code to help in the diagnosis for the bucking condition.

It is puzzling that the dealer cannot pull the code. '94 and '95 are "hybrid" years for scan tools. The cars have OBDII connectors, but the PCMs use OBDI protocol. The tool needs to be able to connect to OBDII and read OBDI. A lot of confusion comes from this. But a dealer should be well aware of, and equipped to handle this situation.

You might consider changing out the PCM for a junkyard PCM from another '95 Bonneville. You should be able to find one for less than $50, and it is pretty easy to change. A properly functioning PCM should store and communicate the code that caused the engine light to illuminate.

In more ways than one, "what we have here is a failure to communicate."