It could be your crank sensor, I just did a 4.6 town car no-start, it didn't generate a code, but plugging and replugging the crank sensor fired her right up. You might have a missed signal that is intermittent and not generating a DTC, the crank sensor is low in the motor and subject to a lot of road GAK and water that fly up on it.

John

 

Where is the crank sensor located..... Thanks, David

 

sounds like your spark is shorting out through the boots under the COP's. I have my old rubbers from when I changed to the Granilli's. You can have them and see if that fixes the problem.

 

Boots are new, i Re-gapped them to .054 last week an actually after i did that it was worse for a day or two... using autolite platinums.......


Also i reset with disconnecting battery and that didnt help out.

 

You Re-gapped the boots, I use autolite 764's. no more platinums for me.

 

re gapped the plugs

 

If it has been doing it since you bought it maybe whoever owned it before you tried to do a self tune or something and messed up the a/f ratio....I'm not sure.. thats a tough one.... good luck though.