Virtually nothing was new for '86 Firebirds. The base coupe received new tailights, and a upgraded "Rally" suspension as standard equipment, featuring 15x7 Rally II wheels. A rear spoiler, 215/65/R15 tires, body-color mirrors and a new lower-body accent paint and stripe were now standard for base models.

The S/E for '86 received the red-backlit instrument cluster, door map pockets, and an improved Y99 sport suspension with larger stabilizer bars, 15x7 aluminum rims, faster 12.7:1 steering and P215/65/R15 Goodyear Eagle GTs.

The Trans Am's WS6 sport suspension package was upgraded again, now featuring 36mm front and 24mm rear stabilizer bars, 4 wheel disc brakes and a positraction rear end.

Standard, base coupe: LQ9 2.5 litre EFI four, 88hp

Optional base coupe, standard S/E: LB8 2.8 litre MPI V6, 135hp

Optional base coupe and S/E, standard T/A: LG4 305 4bbl V8, 160hp

Optional, T/A: LB9 305 TPI V8, 210hp

The L69 190hp 305 H.O. was discontinued during the '86 model year. The engine suffered from fuel boiling problems throughout its production, and was finally canceled. Only 26 Trans Ams had this engine in '86.