Grand AM with problems accelerating

I have a Grand Am 2000 2.4L 4 Cyl. As soon as they will take it to scan it, it gives me the following codes P0303 and P0440 and it takes to accelerate and spends a lot of gasoline has less than the month they did the tuning and cleaning of the acceleration body. You can help me where I can get the service manual.
thank you

good night.
What I understand most that your fault can be caused by a failure in one of the cylinders. Most likely to be cylinder 3 by the code. I recommend that you disassemble the spark plugs and observe the coloration adopted in them after this time of use, if it is there the problem any spark plug should have an enemy color for ignition failure.
Good luck and I hope you have helped you.

P0303
Failure in cylinder 3, check a spark plug, spark plug (perhaps walking the current), and dirty, defective injector, etc.

P0440
reviews the gasoline evaporation system (canister), probably gasoline plug who is sealing well, an EVAP hose. Rota, Evap's solenoid. Stuck, defective, broken canister, etc. Comment.