Eik

I'm wondering if the plugs are on the wrong cylinders, it sounds like it could have happened before you replaced the wires and you put the wires back in the same spots. The engine may run better when it is hotter because the fuel is burning quicker and you may have some fuel in the cylinder when the exhaust port is open so the fuel doesn't burn right away there.

Edit: If not, try this thread https://mustangforums.com/m_3264510/tm.htm

wildride02GT

First off I'd like to say thanks to everyone who has offered their advice. She's still not running good, but tommorrow I will be pulling all the plugs again and checking the coil boot connections. I wish they never used this coil-on-plug set-up, as it makes diagnostics a pain. I will probably be replacing the plugs with something else tommorrow also.(I work at a parts store, so it wont REALLY kill my wallet) Anyways, I shall keep things updated as I work on it. One question, if anybody could explain it to me. I know plugs have different temp ratings, but is it possible that these NGK's are needing the motor to be hotter to properly work? If so, would a lower temp. thermostat help this? I'm assuming that the plugs should be the same rating as Ford's OE, as they are listed in our store system as stock replacements.

stangdriver2007

the ngk tr55's should be the stock heat range like i said i didnt know what was wrong either but it ended up being a brocken spark plug wire id have to bet its the boot were it connects to the coil upgrade to the msd

wildride02GT

Hey Ya'll, again, thanx for the help. Figured out today part of the problem. Since I purchased the car 5 months ago, I have been complaining that the car feels like I'm dragging a boat anchor around. Long story short, I finally figured out that my rear calipers were dragging. So Ford supposedly replaced both calipers, rotors, and pads on the rear, all billed to warranty company. Today I got to work and noticed that my rear rotors were GLOWING orange. Not good. So, dragging brakes explains alot of my problems. Anyways, tomorrow I'll be contacting the warranty company and Ford to have MAJOR work done to it. Thanks to everybody who has offered their knowledge. I'll be kepping ya'll updated.

0hOneGT

I'm sure this sounds absolutely stupid but this sounds exactly what happened one time when I cleaned my MAF and forgot to reconnect it after doing it (I know i'm an idiot). Not saying this is what's wrong, but, asit seems like youtook a lot of pieces apart, i'dgo back and check the little things. Probably won't be much help, but my .02