1996 Pontiac Firebird engine lacks proformance around 60 mp

Engine lacks power... See one of the following: 1.) Incorrect ignition timing. 2) Fuel filter clogged and/of impurities in fuel 3) Faulty or incorrect gapped spark plugs. 4) Air filter dirty. 5) Spark timing control system not working properly. 6) Faulty ignition coil(s) 7) Brakes binding. 8) Auto Trans fluid not correct 9) faulty distributor cap or wires 10) EGR system not functioning properly. 11) Use of sub standard fuel. 12) Low or uneven cylinder compression pressures 13) Air vacuum leak at intake manifold or plenum