OK my 2000 GT just started missing. It is garage kept, but it sat out at work and it was raining like crazy. At first it had code P0307 which said:

-Misfire on Cylinder #7
-Ignition coil, wire, plug
-Vacuum leak
- Injector
- Too high/low fuel pressure

I switched #7 coil with #8. No codes. But still missing.

#7 Plug didnt look bad on one side, but looked a lean, white-color on the other side

Changed the plug. Still misses

I tried Injector cleaner and then Heet, with no luck.

It misses mostly below 2k rpms, and idles without dying.

Can anyone help me? Im trying to not just throw parts at it.

Thanks

 

Well if the thing still missed, did you throw the code reader on it when you switched the coils??? Did it still say 7th cyl misfire or anything??? Might be the coil harness or the coil itself causing it.

 

I cleared the code before I switched them and now no codes...I was just hoping it would be the coil or something simple because I really dont have much time anymore. Thanks for your help

 

I dont know if this works or not, but I ulplugged each coil while the car was running and rpms dropped each time. Does that mean every cylinder is firing?

 

A marginally bad coil can operate for some time without throwing a DTC--how many miles of the car. are they the original COPs, what plugs are you running, what gap?

 

73000 miles
10k on plugs/wires (Motorcraft Platinums .054" gap)
I am unsure of the COPs..they are Motorcrafts so hey could be original

I think I may have cured my problem through a vacuum leak but I am not positive yet