engin knocking last night but now its not

i took my 2000 cavalier in yesterday to have big 10 take a look at it cause the red oil light came on when ever i stoped my car. they checked the oil level and it wasn't bad but they changed the oil and the filter " basic oil change" and the light gose away. the guy calls me a said its all fixed. i drove it that same night about 30 min after i picked it to go to tampa around 30 miles into the trip the power of the car slowed up and i started to pull over thats when i herd the knoking noise and when i stoped the oil light came on. i got a tow truck to take it back to big 10. This morning i went over there to tell them what had happend when i went out to check the car and turn it on i herd it knock lightly once and and then nothing. did i save my enging in time or is it still screwed. also should i try to go after big 10 for not fixing the problem in the first place cause i no a replacement engine is not cheap.

Who the hell is Big 10? If all you asked them to do was an oil change and thats all they had to do, they did nothing wrong. However, if your motor is knocking and your low engine oil light came on i think you have bigger issues. You should have asked them when they drained the pan how much oil came out. If around 4 quarts came out, then i would be worried about your Oil pump being shot. If thats the case, DO NOT go driving your car.

no i told them that i had an oil light on and im not sure why can you find out whats wrong. and instead of checking the presure they filled it up with oil and that just covered up the problem. cause the car was able to cool off now and the engine light went away.

How many miles on engine? Get the oil pressure checked.