so my civic started backfiring alot when i downshifted one day and continued to do so when i downshifted. it has a catback so it seriously sounded like firecrackers in my exhaust so i decided to change my sparkplugs and one of the plug wires was fused/melted with the spark plug, after about a good 2 days of pulling/pb blaster/hacking at it with a chisel i broke apart the plug from the wire in bits and replaced the plugs and wires after making sure everything was clean. drove it for a bit and the car started to loose power felt like it was running out of gas but maintained speed for a bit before totally dying and the temp gauge was maxed out. i had no clue what was wrong with it so i took it down to a garage and told them to look at it and tell me whats wrong and get a call from them telling me they changed the plugs and wires and it runs fine now... i was thinking in my head wtf... ended up charging me 250 for the exact same thing i did cept i did it for 40 bucks, drove about a mile up the street and the temp gauge was maxed out again and in fear of damaging things more than they already were i returned it telling them its overheating and they didnt fix **** but im leaning toward the headgasket but im not sure.

 

Take off the radiator cap.
Does it look like oil is mixed in your antifreeze? If so, the headgasket is most likely the culprit.

I doubt it's the headgasket. It could be a number of different things. First of all, get your $250 back. About the backfiring: have your ignition timing checked.
Have your thermostat checked. I'm thinking your thermostat is probably stuck closed.