Rocky idle, when in gear no power,slow rpm,backfires in front

Check ur oil dipstick see if there is to much oil. and make sure spark plug wires are in right firing order.

In order to resolve this problem you are going to need a different set of plugs even though the smart parts store mechanics say the computer says you need whatever plugs they want to sell you, you need to go with your OEM plugs if not sure call your local dealer and ask the parts dept. what is the name brand and specific length plug you need for your car when a plug is either too short or too long it will cause this problem if they say you have the correct ones then I would check the firing order to ensure the spark plug wires haven't been improperly installed meaning the firing order is off. I noticed you said the plugs were dirty if that was the case and plugs and wires are correctly installed and proper plug then I would have the fuel injectors cleaned try using some lucas fuel cleaner and stabilizer. If you feel wally world put too much oil in check your dipstick on level ground it will let you know if that is the case I would immediately take the car into dealer and have them check the oil pump to ensure it isn't damaged from over working or caused any other damages in your engine take the estimate with explanation of what caused the problem from the dealer to the walmart service manager where you had the tune up done to start the claims process to have them foot the repair cost or for reimbursement and demand a refund .This should get you back up and running correctly. much success and good luck with this. Please Rate Me. And you can always ask me.