Hey,

I've been gone for a while so i haven't had much time to be on here...but i'm back. My 99 GT 5-speed is showing codes as of 2 weeks ago that my auto repair shop cannot seem to work out.
First off, i put a mac prochamber and steeda MILs on my car 3 weeks prior to getting a "Service Engine Soon" light on my dash. i took the car to the shop after the light came on and it was a multiple cylinder misfire code. they replaced cylinder 3 & 6 coil packs and all 8 spark plugs....the packs were warranty but the plugs were 120 bucks installed. then i get it back and light comes back on (this time it's cylinder 8 misfire). so they change 8's plug and say it was a bad plug from the factory. i get it back and light comes on again so they throw a bottle of fuel inj. cleaner and tell me to drive it for a few days. i do that and the light was still on, so i bring it back and they clean all injectors manually and tell me it's fixed. so i pick up the car again([:@]) and i drive it for 2 miles and light comes back on. that was last thursday and i still have the light on. i'm fed up with these guys and i'm gonna bring it to a ford dealer next.
so now i'm sitting here, $120 in the hole and wondering if the original problem was even fixed to begin with. were these guys just part swapping to "try" to fix the problem, or can my prochamber/mils be causing this problem. also is it true that bad coil packs ruin they're own plug, or do bad plugs ruin a coil pack??
please help me guys...this light is pissing me off.

thanks in advance, Nick