Sounds like an O2 sensor issue. Take it to a local autoparts store and have them put a code scanner on it, that'll give you a better idea of whats up.
Lots of great looking cars in here. Here's mine, 1988 Chrysler Conquest TSi (Mitsubishi Starion):
Looks very similar to a US Spec Cheverolet Nova, with minor changes to the front clip. Really nice looking car either way.