On occasion after raining weather I will get what feels to be like a miss fire, motor runs rough.This dosen't happen all the time,just on occasions after more heavy rain, windy and blowing conditions. After you drive and warm motor up good and then it sits for a while it runs fine again. I hooked it up to scanner and it is not throwing any codes, or showing a miss fire everything is ok.Looking under the hood nothing seems to be wet. Has any one else had this happen.This is a f150 5.4 4x4 1999 .Thanks for any help..........

 

Check your distributor cap to make sure it is tight.

 

i'm leaning towards moisture getting into the cop boots. mileage? when was the last tuneup if ever? and was dielectric grease used inside the boots? i'd check that first.

he has a cop system, no distributor.

 

try a doin a tune up first thats what fixed my truck if that dont fix the problem its coils my truck had a occasional misfire i replace both coil packs that fix my problem for about a week then i did a tune up wires and plugs and my truck ran good after that start with a tune up first tho

 

Classic COP failure. My van is doing it right now. Replace the coils and the plugs and that will fix it.

 

Thanks for the help wish I would of did that tune up while it was warm out ,I got all the original plugs and coil packs in it yet.How much will coil packs and plug cost and what make of plugs and coil packs should I use? Thanks Again.Ps no Distributor.......... 56k Miles

 

I'd pull and inspect each COP boot and see if they show any water stains. You might have a hood seal leaking causing a COP hole to fill with water causing a misfire.

You can also run a bead of rtv around the topside of the boot then install them to help keep water from getting inside the sparkplug hole.

 

You have the Coil on plug ignition, no coil paks. You can get them on E-bay from Global for about $90 a set. Rock auto sells Motorcraft plugs for $4.75 each. Use Motorcraft plugs for best results and the Global coils have had good reveiws from people on this board.

 

going to take truck to dealer on thurday and put on computor to see just if I got a bad coil on plug or not.hate to spend money for test but with the cost of COP I think it will be worth it ,kind of want to stick with motor craft parts. also seen some good deals on ebay for used COp that are guarantee has anyone bought these to replace bad COP? Price at dealer is close to $100 for one COP.thanks

 

First rule - don't' buy used COP. That is a total waste of money.

So you are going to go pay the diagnostic fee at the dealer because you don't want to spend the money on new COP? You do realize that you will spend MORE for the diagnostic than if you just purchased a new set of COP off Ebay? So far my Ebay set has lasted as long as my factory set did.

 

Which brand did you buy on ebay I will do this if I sure I getting the right brand that is going to work,I could not find the global brand could you give me a link to there page or the kind you bought ? Thank you

 

Global is the brand (some) people from this board are buying. I just bought a set for my van and I had a dealer service department install them for me because I hate working in that vans dog house. Got my motorcraft plugs from rock auto for $4.75 dealer wanted 14.75 for them. Globals are about $90 a set VS dealer price of about $400. I would atleast get your own parts and have them installed. That will save you allot of money. Dealer charged me $210 to install them in the van. Well worth it.
Heres the link
http://cgi.ebay.com/ebaymotors/NEW-I...3A1|240%3A1318

 

Thanks For the link going to purchase these then decide wheather I want to do the job or go back to the dealer ,dealer here in pa price for COP were $90 each ,way to high for my wallet to replace all of them. Advance auto gave me a price of $45 a piece for borg warner COP And $2.99 for motor craft plugs. So for $90 for set of 8 can't beat the price. Like to here from others that used these so I might post another topic about this brandThanks again.

 

Use the search bar and type in "Global" - You'll see that many on this site use Global coils..

 

Never thought of this or even heard of it. Is this a good idea, anybody? Seems like you'd run the risk of the sealant getting into the cylinder next time you changed plugs. Don't even know if that would be a serious problem as it would probably burn off...but it couldn't be good...at least foul a new plug. But it is worth considering.