Motor Skips

I have the same engine in my Explorer...but unfortunately don't have any insight to offer.

You might want to consider posting the question on a website dedicated to the Explorer / Mountaineer platform. I found the folks at

http://www.explorerforum.com/

to be very helpful when i was researching the vehicle prior to purchasing.

What are the trouble codes?

OBD-II Check Engine Light Trouble Codes

I had this problem a few months ago with my 99 Ford F 250 Super duty with the V10.

It came down to having a small anti freeze drip that seeped down into one spark plug hole and was causing a intermittent short between the coil module and the related plug for that cylinder.

Without knowing how many miles and how clean your engine is I would suspect you may just need a new set of spark plugs and or related components. I do recall that there where several different types of ignition your engine used so you may also have a bad plug wire coil pack or other ignition related component failure causing your problem.

Do a compression check on all cyl and we'll go from there.

This problem is common to fords with coil on plug modules. the modules overheat and fail. Frind of mine with a F150 with a V8 of that vintage has had to replace every single one of them since he has owned the vehicle (has owned it for about a year and a half or so.). I suggested to him to take a beer can and cobble up a heat shield for each one. it hasn't been hot enough for problems to reappear since I made the suggestion, so i don't know if that helped or not.

I believe your so called skip is a cylinder miss firing. If you do not get a check engine light then the miss fire is most likely due to a coolant leak into the cylinder. If the check engine light is lite then read the codes and correct that problem. We see engines that have bad gaskets, head, intake manifold, that allow coolant to enter the engine and cause those types of "skips" or miss fires.

Yep, I've seen many times where is not discernable at low rpm and not time for it at higher rpm but in between you know it's there. Was the very slight beginning of a blown head gasket between cylinders.

I have no CEL. Also I have double checked and have no engine codes. The skipping is just every now and then and not every time I drive. As stated earlier just between 35 and 50 mph, as far as I can tell.

I had a similar problem on a Focus 2003 and found a wire from the harness to the engine almost completely broken from the rocking of the engine. Check your harness where if gets the most flex and move the wires about when engine is running. If the problem shows up then you will need a repair. On some engines the harness was too short causing to much concentrated flex breaking the strands. Problem did not show up for several years after production or use.

As stated, coil failures are very common on this series engine. If it misfires for long enough, it will trip the Check Engine Light with the random misfire code. But this will not happen unless you allow the engine to continue to misfire for a long period. Such as climbing a hill that is perhaps a half mile long. Determining which coil is misfiring is the harder part, as it usually will only miss when under a load, not while idling.

Does anyone out there have a way to find out which coil is bad without an oscilloscope?

one of these maybe?

http://www.harborfreight.com/catalogsearch/result?category=Automotive+%26+Motorcycle&q=spark

That site led me to 901 items. All of the items above $60 will not allow someone to isolate which cylinder is misfiring under load. At least not that I could see. If you found something that will do that, please let me know, and ID it a little closer. Thanks.

Sorry, try this link instead. they have a couple that are similar for older model cars where the plug is not down in a hole.

http://www.harborfreight.com/inline-spark-checker-for-recessed-plugs-97577.html

The vehicle is going into lock-up and overdrive and lugging the engine , you then feel the misfire or skipping. The engine may need a tune-up or coil, how many miles since the last maintainance?

Welcome to the insanity. You are right on the symptoms, and the coil breakdown is common on these engines. But, no easy way to ID which coil. The sad thing is that when we all used a coil for all of the cylinders, and almost any 12 volt coil could be used on any car, the coils cost less than the 8 or 10 separate coils used on these Ford engines.

One simple trick for finding the misfire is to use an IR thermometer and take readings along the exhaust manifolds and look for which cylinder has the lowest exhaust temp reading. You may not feel the miss fire all the time at idle but it will make a noticeable temperature variation on the affected cylinder.

If it does come down to a bad coil you might as well buy the whole set and do a complete change out. When one goes the rest seem to follow shortly behind or at least every Ford I have had that used the independent coil packs did that. If your vehicle is getting up in the miles you can save a fair amount of money by buying the whole set from an online aftermarket auto parts supply dealer. Many of them carry a better quality coil systems than what the factory makes and for a fair amount less. Recoiling my V10 set me back about $170 with the aftermarket coils opposed to several hundred dollars with the factory replacement ones.

I am not up on the exact technical name. I once had a dodge truck with similar issues and I replaced the throttle body position sensor, throttle valve or vacuum advance gadget- I don't remember exactly which widget I replaced - it was cheap ($20.00) and done in 5 minutes - didn't require any electrical intervention - problem went away

good luck