Gatorgrizz27
Well-known member
- Joined
- May 20, 2020
- Member Number
- 756
- Messages
- 888
Bought a 2005 F-350 work truck with the 3v 5.4L. Guy told me it was misfiring and needed plugs and coil packs.
Replaced them all with Motorcraft plugs and aftermarket coil packs (not the super cheap ones), since it had about 5 different types of coil packs on it. Also cleaned the MAF sensor, throttle body, PCM connections, made sure the air intake and box were clear, drained the gas tank and put a new fuel filter on it since it had been sitting awhile.
It starts and runs way better than it did before, but still idles like a cold carbureted truck, and is sluggish accelerating below ~2,500 rpm. Only code is P0354, coil pack issue on #4 cylinder.
I checked all the coil pack connectors for proper 12v and ground signal from the PCM with a test light and noid light. That coil pack reads 0.8 ohms continuity, but my meter reads 0.3 ohms with the leafs shorted. From what I’ve seen 0.5 ohm is fine.
I also did a half ass vacuum leak test with carb cleaner, didn’t find anything, and found the fuel injector for the #4 cylinder isn’t getting any signal. Thought that was likely the problem, but I’ve read the PCM may shut it down due to the fault code. Cats have been removed previously also.
Next step is a compression test, but other than jumping in and troubleshooting the PCM or assuming it is fried, what else is there to check?
Replaced them all with Motorcraft plugs and aftermarket coil packs (not the super cheap ones), since it had about 5 different types of coil packs on it. Also cleaned the MAF sensor, throttle body, PCM connections, made sure the air intake and box were clear, drained the gas tank and put a new fuel filter on it since it had been sitting awhile.
It starts and runs way better than it did before, but still idles like a cold carbureted truck, and is sluggish accelerating below ~2,500 rpm. Only code is P0354, coil pack issue on #4 cylinder.
I checked all the coil pack connectors for proper 12v and ground signal from the PCM with a test light and noid light. That coil pack reads 0.8 ohms continuity, but my meter reads 0.3 ohms with the leafs shorted. From what I’ve seen 0.5 ohm is fine.
I also did a half ass vacuum leak test with carb cleaner, didn’t find anything, and found the fuel injector for the #4 cylinder isn’t getting any signal. Thought that was likely the problem, but I’ve read the PCM may shut it down due to the fault code. Cats have been removed previously also.
Next step is a compression test, but other than jumping in and troubleshooting the PCM or assuming it is fried, what else is there to check?