need help with cav. ASAP!!!!

I recently changed the oil in my 2001 cavalier. I drove it home and when i went back out an hour later, about 10 miles up the road the temp. guage goes all the way to 260. I pulled over quickly to see what the problem is, the engine is not even hot there is antifreeze in it. i got back in the car and drove about a 1/4 of a mile and the temp guage went to 100. now the Trac off light and check engine light and the check guages light come on. another 1/4 and they go off. i turn it off start it back up and it starts but it makes a noise like i had bad gas in it once. but not the second time. went to a friends house for a few hours and when i left it started fine. on the way home it started guage dancing again. i drove about 10 miles and got off my exit to go home and the car died and wouldn't start. it turns over but dont start. and also my heater blows out cold air through it all. plz help asap im lost.

thanks

aaron

When you changed the filter did you maybe break or losen any harness connections? Just a thought.

well we just replaced the knock sensor, crankshaft sensor, the thermostat, and even checked the timing chain. I didn't think about that but after putting the timing chain cover back on we tightened the crank shaft bolts turned the motor over and antifreeze shot out of the cylinder. i believe im up a creek. thanks