Ok, I own a 91' firebird. It has a transplanted L98 350TPI. The other day I drove it with a loose radiator cap. Drove the car 50 miles. Temp looked fine the whole ride there. However when i got to my destination the cars temp climbed to 240! Smelled coolant so i got to the closest hose and added water while the car was running. Alright temp went back down. Now, the car just doesn't run the same. No tell tale signs of a bad head gasket. Runs good unless i floor it! Runs normal, no oil in coolant, no coolant in oil. Idles great,NO smoke, no water in exhaust. Runs cool at 160 degrees. However, I can't figure out wtf happened. I thought i may have bought bad gas. Well, cleaned the pcv valve, checked the fuel filter, checked the plugs and wires, Distributor cap and rotor. Everything is fine. I am starting to think it may be an ignition module issue? Like i said, the car runs normal around town, but when you get on it, it feel almost like a bad plug wire. The power wants to come through but it just feels like something is blocking it. It almost sounds like it is sputtering. Now the exhuast not has changed too. Car sounds more high pitched and hollow sounding. I am starting to think the timing may have jumped? I really need some help on this one. I did disconnect the knock sensor today and the problem amplified! The car barely ran and sounded like it was sputtering a little. Maybe I have a bad knock sensor? I dont f-ing know! Is the ignition timing in that car controlled by the computer? Someone please tell me wtf may be going on here.