Mod (Ret.)

Good point. There's a reason that cylinder #5 is the code being stored. When the mechanic replaced the coil, did he/she replace the spring and boot?

techrep

iTrader: (1)

Swap everything ... COP / boot and spring / plug / injector with #1 and see if the code follows.. While the plug is out check cylinder 5 compression.

Nosajb15af

Had the same issue when towing my boat. Remove and clean TB and clean mass air sensor. After that, fixed problem immediately.

I went through hell figuring that out. I replaced plugs, filters, fuel pump module, COPs, compression checks, exhaust cat check, intake, injectors... Finally I talked to my buddy who is a ford truck tuner for Dallas mustangs and he said to clean or replace TB and mass air. Fixed the problem. He said strangely that can even throw the AC into chaos. I was getting a misfire on cylinder 1 and 5.

grumblegeek

I replaced the coil myself and yes I replaced the entire assembly.

grumblegeek

Cleaning the MAF sensor is a good idea. Will see if I can knock that out this weekend. I had the throttle body exposed while I was replacing the fuel injector and it was clean.

grumblegeek

Thanks for the feedback.

Pardon my shadetree mechanic-ness. Most I've gotten inside an engine is replacing the valve cover gaskets on an old Jeep.

Would a compression problem only show up under load? When I gun it to get onto the freeway without a load should I see it show up then? Seems like low compression would show up under other circumstances.

Mod (Ret.)

Under load, any type of ignition problem is going to show up. It's a possibility that the compression is low, but I'm not on that yet as being at fault. It still sounds like an ignition fault to me.

Wiring/plug to that coil (#5) good? Its possible that you have a bad plug, even though you replaced it; maybe the replacement was bad.

I like techrep's idea of moving everything from #5 over to #1, to see if the fault code changes.

Nosajb15af

Mine was flashing under heavy load due to a severe lean condition. Hopefully my valves didn't suffer too much. I could reproduce the problem no issues by max throttle getting onto the highway. 1st gear would do good until 3k rpm then struggle, 2nd gear would bog severely at 3k then the engine light would start to flash. Other then a severe load, truck has no signs of problems. Cleaned MAF with a MAF cleaner, cleaned TB, and cleaned butterfly. Too bad a MAF clean wasn't first on my list. Spent good time and $ with other parts. Oh well, at 120k miles, all the new parts definitely didn't hurt the truck.

Mod (Ret.)

It sure seems off though that a #5 mis-fire code appears with a dirty MAF.

Nosajb15af

Agreed, hence not my first go to. I figured for sure spark and started there.