98 XLT 5.4 Need Help With Code P0354
 

Need help with a code P0354 (Ignition Coil “D” Primary/Secondary Circuit).

This started with a P0304 (Cylinder 4 Misfire Detected) and P0171 (System Too Lean) and I changed out the coil pack on cylinder 4 with a new one. I took the coil pack that was on 4 and put it on cylinder 1 (since this is easy to change) and still have severe hesitation. Now I am getting a P0354 code. I measured resistance on the new coil pack and the one that was in cylinder 4 and they were the same also I was curious if I would get a misfire on 1? No codes for 1 and I drove the truck around today to try and get more info. I hate to bring this to a shop since I already tackled the hard part of changing the #4 COP.

Any suggestions on where to go from here?

Your P0354 indicates that the electrical circuit for the #4 coil is open. Probably, the connector is not properly connected or you have a bent pin or the harness was stretched/pulled and is now open.

Steve

I caved in and took it to the shop down the street from me. $75 for time and they changed the spark plug in the #4 cylinder. I had already changed the coil pack on the 4 with a new one? Now all is well and running normal again.

A spark plug won't cause that fault code. They probably just plugged it in.