I recently bought a 1997 Mustang Cobra with 110k miles on it. The only mods are a exaust, intake, throttle body, and short shifter. Anyways, it keeps throwing different codes. First time i checked it said cylinder 5 was misfiring. Next day it said it had a high idle. Next day it said cylinder 2 was misfiring. What are the things I should check? As far as I can tell it does not have a vaccuum leak. I have also cleaned with the spray seafoam through the throttle body. Im not too good with cars but this problem can be cause by bad spark plugs, wires, coils, vaccuum leaks, dirty inkectors, or valves am i correct? Where should I start troubleshooting?