E450 V10 Engine Miss

[whemme]

My 2000 Ford E450 motorhome with the V10 engine has a recent one cylinder miss at idle. As soon as I rev up the engine a little, the miss goes away. 108,000 miles on the V10 and all spark plugs and coils were replaced at 98,000 miles.

Anyone have an idea as to the possible problem? Partially plugged injector, bad spark plug, bad coil, valve problem???

[path1]

See if any codes show up and fix what code says... If no codes show up because not big enough problem yet...unplug a coil over plug (COP) and see if miss gets worse or better or maybe the same. If worse then that cop is NOT your problem, and that cop is working right, plug back in COP and go to next one. Process of elimination. Be carefull of the small rubber gasket in connection, pain to replace and easy to loose. If your cop's turns out ok, my next would be injectors. Injectors same as above. The parts you used when you changed them prior...I only use ford replacement parts, because I've had to many failures with brand X. If still not fixed right, break out the book and go step by step. I carry a spare cop and injector.

Doing the above is assuming you've already looked for the obvious...vacuum leak from cracked rubber hose, fuel filter etc. Did you put anything in tank to "clean" injectors? Maybe it did to good of job... After giving mine a present around 90,000 miles and replacing a bunch of stuff I treated it to some Seafoam. The seafoam freed up small filings from when OEM drilled hole for generator fuel line. Filings broke free that were stuck in bottom of fuel tank all this time. And they plugged up fuel filter and filter in "bypass mode" small filings were caught in "injector bucket". And you might be in the year models that Ford spark plugs were not one of Fords better ideas. 2 piece plug then not enough threads and spitting them out of hole etc.

[ron_dittmer]

I too heard bad things from those parts made in China.

One other thing I suggest is to remove the dog house and inspect the wires for rodent damage. They love to crawl up high and chew on wire insulation which can happen during outdoor winter storage.

[wearenh]

just changed all 10 of mine recently, and my miss went away completely

one question... did you use motorcraft coils, or the chinese eBay ones that cost 1/10 the price? ... I have heard all kinds of bad stories about the cheap ones

[carringb]

Were boots changed when the plugs were changed? If not, probably should change them. If they are good, you should scan for codes, and chances are it will show which cylinder is missing, and then swap out the coil.

[MDKMDK]

I had an '02 Ford V6 with spark plug coils, and when they went bad it started popping engine miss codes. Maybe the plug coils are failing? If it has that type of plug. Just a wild guess.