ok we got the car a few montsh back it was doing great we put a cold air on it high flow cat and custom 2.25 exhaust.... wires plugs (ngkiridium core) and higher output coil but recently... i have been noticing im not accelling very good (i got beat by a cavalier that had just a cold air) she seems like she wants to go but its just not happeneing also i been getting alot of rattling noises but cant find the culprit some one HELP ME!!!!!!!

 

oil change?? dirty spark plugs?

 

valve adjustment?