If you mean it feels like it's losing horse pwr, then you may get lucky and all you have to do is check and service your Transmission Fluid.
A 1980 Cutlass Supreme could have come with either any one of these Turbo-Hydramatic transmissions: TH200C, TH350, TH350C, TH375, or TH400
You could try a 3.1L that is what I have in my 95 Cutlass Supreme SL
diesling is caused by bad spark plugs
Check the crank sensor
nope, bad head gasket..
I really don't think that's possible.
It could be the brake fluid reservoir is low and is telling you that the brakes need attention.
Yes you could but it has a neutral safety switch for a reason.
i have a 1995 Oldsmobile cutlass supreme it is located in the dashboard on the passenger side in the panel by the front door its a small panel when you take it off it list all of the fuses inside Could be your flasher too.. that's on the drivers side under the dash.
you may either have a weak battery or your alternator could not be producing enough volts. Could also be a combination of the two.
Could be in need of a tune up. Start with replacing the spark plugs and spark plug wires.
belts bad ac compressor timing chain.listen to see where the sound is comming from.that could help alot.