Hello all. I have a 99 chevy lumina with the 3.8 Liter engine. I have owned the car for a few years, and has been my daily driver. The other weekend I was driving it to my parents place, I went to pass someone, and it started acting boggy, and loosing acceleration. I stomped the pedal to the floor, and it smelled like firecrackers. I looked down at the temp guage, and it was rising - fast, and it topped out at 50mph. Shortly after, the car dies, and I pull over on the side of the road. I noticed steam coming from under the hood - the overflow fill bottle, and the antifreeze was boiling, and proceeded to shoot the cap off the fill tank, and hot coolant all over me! OUCH. It wouldnt start when it was hot, but after it cooled down a bit, it would fire back up. After I got it pulled home, and it fully cooled, I started it up, and the motor seems to have a fast knock noise, not at idle, but anytime the accelerator is pressed. Anyone know what might have went bad/make a knock if it got this hot? I pulled the heads and intake man. off, thinking it was a valve,push rod, or rocker, but none of them loked bad or had any abnormal signs of wear. I replaced the intake gaskets a few months back - about 4-5,000 miles ago, but didnt do the head gaskets at the time. Anyone know or have experienced this problem? Where would the knock be coming from, and is the motor worth fixing - 186,000 miles , and any ideas of what would have made it smell wierd - then get real hot right after? Thanks a lot guys and gals for all the input! ----- Jon.