Been having an issue with the car where the transmission is very noisy and make a very noticeable rattling sound when hot. It also struggles when going up any kind of incline. On steep hills it bogs down quite a bit and seems to have no power. When car is cold there are no issues. With the days slowly getting warmer this will be more of an issue and I need to have some idea of what I might be looking at. As a side note, I do have to change the crank position sensor. Could this be related?

Are you sure the rattle you are hearing is not your catalytic converter(give a love tap with a rubber mallet)? If partially plugged, would cause lack of power....

Why do you have to change the crank sensor?

Squirrelly tach. It'* all over the place between 0 and 2000 with no actual change in revs. Will check into catalytic converter. Thanks

Squirrely tach? On a 2000+? With no change in RPM? That'* not your CPS. If it was your CPS your engine would be idling bad if at all and you'd probably have a CEL. I'm suspecting an electrical issue somewhere under your seat or your instrument cluster. The 2000+ Bonnevilles are know for electrical issues under the seat.

I agree with Mike. When the crank sensor fails the engine shuts down like you flipped a switch. The issues you describe have nothing to do with the crank sensor.

Didn't think it was a likely cause, but figured to give all info I could.