when it gets almost to operating temp, it just clears up like you turned a switch on. but when cold runs terrible... any Idea's,, I'm sure its something simple...it started after I flushed block and radiator.....thanks...H41

97 5.4

 

Bad plug, coil, coil wire or leaking fuel injector. Not a 4 in 1 coil type coil, but the COPs type.

Any one of these can cause this. If you have a CEL on, you can check it that way. My 98 has a cold start misfire. I know (experience of being a wrench) that my misfire is an injector. The misfire, the smell of exhaust, and the general run ability tells me that is my problem.

Yours can be any of the above. Start with the CEL and go from there. good luck

 

thanks Ak,, had a feeling might have gotton some water spray up in there somewhere when flushing,,but tried to be real careful not to.....my cel light quit working about a month ago,,, need to replace bulb.....I will try to get a code check today and see what it say's....thanks for the reply man......H41

 

only code it showing is po141,,,Bank 1- sensor2,,,I already new that was bad,,,,update: the cold miss has quit,, but at Idle, it has a dead miss,, but runs good down the road,,,like a bad plug wire in the old motors used to act,,,,,any thoughts there? I just don't know these newer motors well enough to pinpoint the problem....thanks H41

 

If it is dead miss at idle, unplug each coil one at a time. See which one doesn't make it run worse, check codes before this, for reference. Which cylinder didn't make it run worse is the problem cylinder. Check that cylinders plug and coil, stethoscope the injector make sure it clicks like the others! GL!

 

Figure out what cylinder is missing and check your compression low compression on a cylinder will cause a miss at idle but won't be noticeable at higher rpms

 

thanks guys gonna check it today. appreciate the help....H41

 

This has COP written all over it. Ford made a Sh1tty COP design, when it gets cold outside they are more prone to failure. Do what others have said- plug each COP one at a time- when the misfire goes away, you have found the bad COP. Also replace your plugs at the same time.