My 99 F150 5.4 is setting the p0354 code. I have replaced the Coil, Spark plug, Fuel injector and it hasn't seemd to make a difference. Where should I go form here? I was going to do a compression test to see whats up. Any suggestions? I checked the wiring and I didn't see any abrasions. I hooked an old coil and spark plug, started the engine and it seems to be firing okay. What should the compression reading be? Can an internal problem cause the p0354 code to set?

 

after you replaced stuff did you reset your ECU? If not unplug the negative terminal of your battery for a few minutes then plug it all back up. That should turn your light off. If not there is still a problem.

 

I did have the battery disconnected while working on it, and I reset the check engine light with the scan tool. The engine is still missing on the number 4 cylinder as it doesn't seem to make a difference when the coil is plugged in or not.

 

Miss read original post

 

Since this code refers to the coil primary circuit, it shouldn't be mechanical issue.

I looke around a little and they discuss it in some detail here.

https://www.ford-trucks.com/forums/6...ode-p0354.html

Note, the post with the most info seems to require you to have html or whatever turned on -- or else just ignore all of the
</td></tr> <tr> <td style="border-right: medium none kind of stuff

Good Luck,

hj

 

Let me shorten this a bit for you.
Code 354 is cylinder 4 open coil primary circuit.
Check that you have 12 volts to ground at the one lead on the plug.
If yes, use a VOM meter set to resistance to read 10,000 ohms.
On the other lead test for about 10,000 ohms to ground looking back at the computer.
If you see very low or very high resisitance, the solid state switch is faulty in the computer.
If this should be the case, the computer has to be replaced.
It is a dealer job. They will have to get a unit based on the original ID.
They will go online to a FORD data base with your VIN to access your original build data.
This allows a copy of the original program to be down loaded for flashing the new computer.
If PATS is involved, you need 2 keys to complete the job.
Hopefully it's not the computer.
Good luck.