I have been chasing a misfire on a 04 screw 5.4 3v with 212k. I THINK i have in narrowed down to a bad injector. It sounds ok but not really a way for me to check it under a load. Should I replace the one and see if that clears up my problem and if it does replace them all? What brands are ya'll using? I couldn't find a link on here suggesting any one particular brand.

 

Have the spark plugs been changed? If so, then I would suspect a bad COP on the misfiring cylinder. And if not, I would start with changing the plugs and seeing if that clears the problem.

 

I changed the plugs 12k miles ago. I did replacer the COP and plug in the cylinder as well. I moved the coil to #1 and the code still showed up on #4. I thought I had a broken wire in the COP connector, so I replaced that. I guess I am hoping for a bad injector because I sure don't want something mechanical. BTW the code is P0354

 

to test for something mechanical do a compression test on your engine to see if you have a something deeper before throwing more parts at it

 

Original thread:

https://www.f150online.com/forums/20...d-weather.html

With that code I think it's more likely a bad wire somewhere where you haven't looked yet.

New Motorcraft injectors are expensive as hell - almost 100 bucks at rockauto.com. I dunno how their remans are but they are 1/3 the price.

 

I have thought about a bad wire, but I have no idea where to start back tracking from the coil connector. (I don't want to cut open the harness). I have thought about replacing the whole harness, but I can not seem to find a part number. GLC, you suggested I might have a bad injector on my other thread, and I trust your expertise, so I thought about just changing them all out. I am assuming you would recommend the Motorcraft? I am goinig to see about doing a compression test and going from there.

 

At that price, I wouldn't just throw a set of injectors at it. Have you tried Techron in the gas?

Read this:

http://www.obd-codes.com/p0354

After reading it myself, I now doubt that you have a bad injector. Try the prescribed troubleshooting.

 

Here is todays events....decided to do a compression test this morning. While I had everything out of the truck, I inspected everything. Plugs, coils, boots, connections. I had one plug that the electrode tip was gone so I replaced it. Compression came back within 5% of a cylinders. Decided to move plug and COP from #4 to #1. Re installed everything, with anti-seize, di-electric grease, all of that stuff we do when we change the plugs. Start up the truck and it sounds great UNTIL I put a load on it. I put the park brake on and put in 1st gear and it wants to lug at 500rpm. Doesn't seem to miss as I drive around the block just when I leave a stop sign. Pull in to the drive and put it under a load and hold it at 1900 RPM and I get the miss. Enough to pull a pending code. P0354 again. AS it idles in the driveway, it smells like it is running rich. When I was doing the compression test, with all the plugs out and injectors disconnected, I thought I heard a drip. I could'nt tell where it was coming from. Could an injector that is stuck open, possibly "drown" a cylinder to where a COP "thinks" it does not cause a spark? I am planning to pull the fuel rail tomorrow to move the #4 injector to see what happens.

 

When you pull the fuel rail, take any injectors that stay in the engine and plug them back into the rail. Make sure all 8 are secure in the rail. Lay out sheets of paper under all the injectors and turn the key on. You will immediately see any injectors that are leaky.

 

Well, I did not find any leaking injectors. Not the easiest thing to do when it is 45 degrees and winds are blowing 25mph. I went and measured the hertz on the connectors for #4 and #2. Number 4 showed 11.4 hertz and 6.7 hertz on #2. I am going to hopefully get to check the rest tomorrow. Is it possible that I had the PCM go bad? If so, do I replace it or would a reflash fix it?

 

Where can I find a pin out diagram for the system grounds on the PCM?

 

Here is something I have.

https://www.f150online.com/forums/me...0&ref=gnr-prev

https://www.f150online.com/forums/me...0&ref=gnr-next

 

Thanks Pappa, I am assuming that the 2007 and 2004 for are the same.

 

OK, Finally took it in to the dealership for a diagnosis. Wife didn't want me wasting another weekend under the hood. Dropped it off last Tuesday. Called them on Friday to get an update. First thing the told me all the plugs were bad due to being loose and the needed to be replaced before testing anymore to eliminate those as the issue. Is it possible that a loose plug could cause the P0354 code? I just did a compression test and might not have tightened them down enough. I also might not have tighted #4 enough since that one is the hardest to get to.

 

Very possible, 3V plugs need to be torqued to 25 ft/lb with antiseize on the barrels but NOT on the threads.

Real world service life on stock Motorcraft plugs is about 100k, but Ford is now recommending 60k changes due to the removal issues. Aftermarket plugs aren't really any better for life and can be considerably worse.