What type of oil does a 1991 Pontiac Firebird uses?

A 1991 Pontiac Firebird's recommended oil type depends on the engine it has. There were several engine options available that year. To know for sure, you need to check the owner's manual or look for a sticker under the hood.

However, generally speaking, a 1991 Firebird likely used conventional 10W-30 oil. The owner's manual might specify a higher quality oil such as synthetic blend or even fully synthetic depending on driving conditions and engine type. Always refer to the owner's manual for the specific recommendation for your Firebird's engine.