I've replaced the plug, injector, and COP on the #2 cylinder. During the day, the truck runs fine. When I drive home late, it has a 'shudder' going up a long hill. It acts just like a failing injector, but I've eliminated that option.

It only does this uphill and seems to only do it when the truck has barely warmed up.

I'm all out of ideas. Any suggestions?

Code says misfire p0309 cylinder 2

 

You sure you actually changed #2 cylinder? Passenger side second from the front?? Could be your PCM. The drivers for the injectors are in the PCM, so maybe the driver is bad..

 

Also, P0309 is misfire in cylinder number 9.

 

What kind of plugs you put in. The guy that did mine put in autolite cause he said he went to a class or something on these trucks. He said they say run Autolites cause they are better. Well he sent me to his buddy after not knowing the problem and his buddy tore into the motor and stuff we found out it was the plugs. He put in 8 brand new motorcraft plugs and it runs like brand new now.

 

Just to remind everyone of history, Autolite was owned by Ford prior to 1973. Our Federal government, in its infinite wisdom, filed a lawsuit against Ford Motor Company under the Sherman Anti-Trust Act alledging that Ford created a monopoly in the auto parts business or some other drivel. The government won the suit and Ford was forced to sell off its Autolite brand to the Bendix Corporation which later was acquired by Allied-Signal. It appears that Ford continued to use Autolite plugs that were relabeled as Motorcraft after this time because the Motorcraft and Autolite brands look identical except for logo. As for the plugs that our 5.4's use, I can't say for sure; but it appears that still applies as the Autolites are still assembled in the same manner as the Motorcrafts and are still prone to breaking upon removal. It seems that Champion plugs are the only brand that the two pieces are fused together so as to appear as one piece and not break off during removal. The Autolites are crimped like the Motorcraft.