My check engine light came on, so I went to my local AutoZone and had it diagnosed. I found out that I had a miss fire on my fifth cylinder in the ignition coil. So I replaced the ignition coil, spark plugs and spark plug wires. It seemed to work fine for a while, but then the check engine light turned back on. I went back to AutoZone and had the same diagnostic done and got the same results. It will turn off ever so often, but the check engine light stays on more often than not. Does anyone have any suggestions or ideas of what could be going on?

It's not really going off you have two levels. A pending code which is when the PCM detects a fault but it's not met all the parameters to turn the light on. Then you have a hard set code that turns the light on. Now you could have gotten a bad coil. What brand did you use? Some of the aftermarket are notorious for going through two or three before you get a good one sometimes. Also check your plug gap if it's too wide you can get misfires. Also dirty fuel injectors or vacuum leaks can all mess with the AFR which can sometimes show up as a miss fire code.

Sent from my 2PS64 using Tapatalk

__________________
New DD-2009 Mustang GT/CS candy apple red

(For Sale)2003 XLT 5speed swap, Hurst Shifter, STX valance SLP drop coils, thunderbolt hood scoop,Screamin demon coil, Flo-pro super v, 1.8:1 Morana rockers, Roush sway bars, SCT tuned by Fred at Rogue, Taurus E-fan, 15x8 Torque thrust wheels gunmetal on chrome, Led 06 tails and smoked HID projectors, mud flap delete, painted drums/calipers, Rear flip kit.