[Foxx]

Hey all. I currently have a truck at work that just has me baffled. It's a 1999 F-250 with a V-10 and an automatic. It has 200,000 miles and an engine miss.

When it first came in, the SES light was on with a code for 'Random Misfire'. I replaced the spark plugs and plug/ coil boots, cleared the code and drove the truck for about 30 miles- everything was fine. The truck came back the next morning, with the same complaint. There's no SES light or code this time, though.

Around 1500 RPM, under load like going up a hill, you can feel the truck miss. However, the Modis (diagnostic/ scan tool) doesnt show anything. It says 'Misfire- No'. However, if you get up to 2700-3300 RPM, then the Modis shows 'Misfire- Yes', but you cant feel it.

I'm pretty lost now. I think it's a coil failing, but without any trouble codes I dont know how to tell which one it might be, and I cant just start swapping them out until I find it. I've watched the injectors on the Modis while it shows a miss, and they appear okay.

Does anyone have any suggestions?

 

[Foxx]

Well, it's running now. I played with it for a while this morning, then finally convinced my boss to let me take it to the Ford dealership and have them put their scanner on it. Low and behold, they turned up a Misfire on Cylinder 3. I put a good used coil on it, and that fixed it.

The moral? There's nothing like having the right tool for the job.

 

[fordguy09]

any time you have stalling missing, and worsening on hills, etc. My first thought is check plug wires, plugs, coil. Easiest but most "shocking" is leave vehicle running, and listen to the motor, one by one take off a spark plug wire, if the wire is working well, it should miss bad, and sound like [censored], if it is bad there should be little or no difference, if you ever do this dont be surprised to get a little shock. But if you change the wire, and it doesn't fix the problem, replace your coil pack. Thanks fordguy09 This is the second person who couldn't figure out they had a bad coil pack, did your dads, or uncles ever teach you anything, dang.

 

[doczenith1]

[ QUOTE ]
one by one take off a spark plug wire

[/ QUOTE ]

Did your dad, or uncle ever teach you anything, dang. The V10 does not have plug wires!

 

[jade97]

It took a month of random intermittent misfires for my truck to throw a code......a long month.....

 

[madweazl]

I'm having a similar problem right now, though self inflicted I think. The other day some friends went mudding having never played in the mud I took it for a spin. Truck did great but after I washed the engine compartment down it developed a miss. A friend has a very nice scanner so we hooked it up and it threw missfire codes on 3, 8, and 10. I figured some water got past the the boots. I pulled them and 8 did have a bit of moisture. Put it back together and had no change (miss is intermitent and most prevalent around 2000rpm). I swapped the coilpacks with 1, 5, and 9 to see if the problem would follow the coil packs. Ran the codes a few minutes ago and now 6 popped up (didnt touch that one) along with 3, 8, and 10 (which may have remained from before the coil pack swap as I didnt clear the codes at that time). All else looked well (injectors looked fine on the scanner).

I'm waiting for the truck to cool down and I'll take a look at 6 and rescan if its still acting wonky. Any other ideas one what I can look at?

 

[Pappy19]

My son-in-law has an Expedition and was anal about washing his engine. He kept getting a miss now and then. He finally changed out all of the plugs, boots and coils. when he was complaining about the crappy Ford engines anmechanic told him never to wash his engine no matter how dirty/filthy it got as it would ruin the coils. After he changed out all of his, no more engine washes, no more misses. Runs great. I don't plan on washing my V-10 except for a little around the edges.

 

[madweazl]

I clean it out at least once a month but this time it was pretty muddy so I washed it really well (too well apparently lol).

If the coil packs were bad the cylinders I swapped them with should have tripped codes, right?

 

[Steve F.]

[ QUOTE ]
[ QUOTE ]
one by one take off a spark plug wire

[/ QUOTE ]

Did your dad, or uncle ever teach you anything, dang. The V10 does not have plug wires!

[/ QUOTE ]

I think a nicer reply would have been...

"The 6.8 has no plug wires, but you could disconnect each coil over each plug."

Wasn't that a bit nicer?

 

[Snake Eyes]

[ QUOTE ]
I think a nicer reply would have been...

"The 6.8 has no plug wires, but you could disconnect each coil over each plug."

Wasn't that a bit nicer?

[/ QUOTE ]

Did you read this whole thread? Or even just the post doczenith1 was replying to?

 

[Steve F.]

Yes I did... I guess I should have quoted both, but... Two wrongs don't make it right. Also to me it looks as if fordguy09 was talking about "a gas engine", not "just" about the 6.8. Yes he shouldn't have typed what he did to get quoted by madweazl, then by me sticking my nose into it as well. I could go on and on, but best to let it move on.

 

[madweazl]

No quotes from me /ubbthreads/images/graemlins/laugh.gif I'm making progress, only cylinder 8 is still showing a misfire but I cant feel it. Must be very intermittent right now. I'll pull the plug this evening (they have about 2k on them right now) and check it out.