Took the cutlass out to the grocery store and as I parked and shut the car off, the engine hesitated a bit (like didn't want to shut off) and then followed by a burning smell inside of car. I popped the hood and verified that there weren't any signs of fluid leaking or the burning smell. The smell is definitely inside the cab. I went inside the store for about 15min and then back to the cutlass and started it back up normally. The burning smell went away as I drove off. I did notice that the cutlass lost a little acceleration gitty up or so it seems. Any suggestions on what may have happened. This is for my 1970 supreme with TH350.

thanks!