91 Trans Am - Two different problems

my '91 Trans Am (305" TPI) has developed two problems:

1. If it gets cold enough during the night (temp below +10° Celsius), when I start the car in the morning, it makes a rattling noise (not very load) as long as the transmission is in Reverse. After driving the car for half a mile or so, if I stop and engage Reverse, there's not a bit of a rattling sound anymore. The transmission shifts fine, no error codes are stored.

1. The oil pressure gauge seems to go crazy now and then, especially when I have to stop at a redlight, it jumps up to maximum scale, dances around between middle and maximum scale. When I put my foot on the pedal to continue driving, the oil pressure readout returns to its "where it should be" value.

Besides those two annoying problems, it's a great car! Any ideas?

Best regards from Germany,

Markus

I can't help you on the transmission problems but for the second problem, I'm almost certain that it's the oil pressure sender. It's found right above the oil filter. GM Oil pressure senders are known for their failures.

-Bruce