Have 2002 F250SD 6.8 with 53,000 mi. Missing under heavy load. It did it about 15,000 ago and was bad coil. Dealer wanted to replace all 10 because they didn't know which one was bad. I bought one and kept swaping coils until I got the bad one.
It has to be under heavy load to miss,... pulling 12,000 lb 5th wheel up hill.
Is there an easy way to figure out which one is bad? <!-- / message --><!-- BEGIN TEMPLATE: ad_showthread_firstpost_sig --><!-- END TEMPLATE: ad_showthread_firstpost_sig -->

 

Any auto parts store (at least I know Advance Auto) can check the codes and tell you which cylinder is misfiring. My 03 F150 had a bad coil and they read it as #5. I replaced it and fixed it. Just be careful with the correct cylinder sequence. My Dad recently had a coil fail on his 03 F150. They read the code as #3 cylinder. I wasnt available at the time so he asked them which cylinder was #3 and they told him drivers side bank 2nd one back. He changed that one and still had the miss. At this point he got in touch with me and I told him he changed the wrong one. 10 minutes later and he had it purring like a kitten. Ford Modulars are like the old Ford motors. Passenger side cylinder numbering from front to back is 1,2,3,4,5. Drivers side from front to back is 6,7,8,9,10.

 

I 1st took it to the AutoZone for their free scan.... well the o/d light was flashing and they checked the codes, turned off the light and diagnosed it as a bad transmission output sensor and told me to take it to a transmission shop.... I knew that wasn't right. Took it to a local repair shop that seems to be pretty good. Drove it under load with the scanner hooked up and they told me that with these kind of coils there is no way to tell which one. Took it to Ford Dealer and they checked it in the shop.... of course charged me $90... and told me the same thing..couldn't find anything wrong... no way to tell which one... and to replace all 10 coils at the tune of $1,000.

Has anybody else had this kind of experience? Or am I just surrounded by people that really don't know what they are doing?

 

I don't want to sound rude, but are you sure its a miss and not bad ping? Try a tank of premium (91 min, look for 93-94) and run those hills again.

 

Sure it is a miss.... last time same thing and the coil fixed it.

 

A good scanner can read the cylinder misfiring (pending codes) and for SURE a dealer has access to such a scanner. They are giving you a line of BS on not knowing which one it is unless there is no misfire. Keep in mind that a CEL will NOT be triggered on a misfire (unless the COP completely fails or is diconnected) but the PCM WILL keep track of number of misfires per cylinder. With my Actron 9180 scanner I was able to identify the two bad COPs I had by it showing me the number of misfires on each cylinder.

EDIT: If the OD light is flashing then there is a transmission code indicating an issue. A misfire would not trigger the OD light.

 

First, order a set of new plug boots, dielectric grease the hell out of them, blow out the plug bores and reinstall the COPS. Alot of times the boots are the culprit.

 

Thanks, I will try that. Also will ge the scanner suggested by the other guy. only $140 on line and I paid other people more that that to give me bad information.

 

Unfortunately, sounds like the dealer got ya'. I had a bad cop in my truck and the dealer was able to pinpoint which one it was, and even gave me a readout of all the other cops and which ones weren't performing up to standards.

 

I haven't figured out everything that happened and what Monster-4 is telling me. I guess "the rest of the story" is worth telling.
The problem first started when I went to back my 5th wheel in after a 100 mile easy tow. The engine stalled, wouldn't start and the OD light flashed.
after 5 min the engine started ran rough but got unhooked, it stalled later at a gas pump and ID light flash. After I found and replaced the bad coil I asked the dealer about the whole thing and they told me that the engine miss caused eratic trans output and that is why I got the trans output sensor error code. I haven't had the OD light or stalling problem this time.

Monster-4.... will that scanner work while driving so I can check it real time?

 

Sounds like you have an engine ground issue.

 

I was thinking that this MIGHT be the case if the engine was bucking enough to fool the sensor. In fact I started to write this in my EDIT but decided I didn't really have any real knowledge if that was the case.

Most lowend handheld scanners (including the Actron 9180) are not going to show this data in "real time" but you can read the codes and pending codes at anytime even while the engine is running. It just takes a deliberate action by you instead of a constant automatic refresh.
Really in this case (misfires) the PCM stores it as a "pending code" and just like regular codes it stores it until reset (e.g. by a scanner) so there is no need to read this in real time. At anytime after a misfire you can read it until it's cleared from the PCM.

 

Generally, on the 1999-2004 2-valve V10's, you won't get a code for the misfires.

You have to check the misfire counters, which are Ford extended parameters, and they will tell you which cylinder is misfiring. If Ford themselves can't tell which cylinder it is, ask more questions. Are all cylinders showing some misfires? Or none? Random misfire counter incrementing? Things like that.