I wanna double check this 99 5.4 what should the plugs be gapped at and if I test a cop with an ohm meter what setting should I use on the ohm meter and what should it read If the cop is good. Ive been checking into this friend at ford garage tells me one thing chilton book says one thing and I read on the internet a completely different thing so somebody set me straight please

 

Gap should be .052-.054". This should be printed on the emissions decal under your hood if it is still there.

Resistance readings of COPs are seldom an accurate indicator of the condition of the part. That said, the primary is usually less that 1 ohm while the secondary is usually around 5.6 Kohms (as referenced to the primary).

Most commonly, COPs fail either 1) internal insulation breakdown that allows internal high voltage arcing or 2) rubber boots break down and allow arching through the boot to the head.

Make certain you use proper plugs. Also, be generous with the dielectric grease when reinstalling the COPS.

Steve

 

Well I put all new plugs and coils on today and Im still having problems. I just cant narrow this down Im chasing my tail at this point to be honest I think it was missing less before I started oh well back to the old drawing board.

 

u can just pull out on the COP some and it should have enough spark to ark down.. just dont touch the engine block lol or u will get a shock. but thats one way to see if its sparkin! have u checked injectors sometimes a stuck or clogged injector will mess u up

 

I'll bet you using the wrong plugs, just a hunch. What brand and what are the numbers. New Plugs and COP's ?? She should be running great!! Gap specs between .052 -.056, .054 is optimum.

 

I put the motorcraft platniums back in it same exact plug that came out. Yes I was surprised also Im starting to think a trip to the local garage is coming

 

You want help you got it here, allot of people in this forum that know there sheet!! First thing to do is to put that ohm meter the frick away, won't do you no good on these COP's - never have I seen or hurd of a COP failing in this way - they fail under a load, but intermitently, so very hard to detect and test without a mode 6 reader and history report. This problem can be solved here - need more info than your posts provide - how did your problems start and what have you done , any MIL - (check engine light) What's the storie and try not to leave anything out. Read the numbers on the plugs - it doesn't matter what you pulled out, if they are indeed the same then grab an old box and post the numbers. The more info, the better your chances on solving and saving allot of cash. You don't want to know what the dealership would charge, but it might do you some good to pay for an hours labor and let them tapp into your comp to see what's going on. I wouldn't go any further than that at the dealership or thru a mechanic, that's when the numbers start adding up quickly. Explain here and I/we will try to help ...

 

Ok heres the deal my truck has been running great. stopped to get beers one night after work drove approx 25 miles started truck up missing real bad got home, the next day missing even worse low rpms and high rpms checked all connections,dry gas,checked fuel filter,then after reading this site which buy the way I agree 100 0/0 with you jbrew people seem to know there sheet! I checked the coils 2 times and plugs coils seemed ok going buy the book plugs didnt seem bad to me either but anyways after much debate I had a set of new plugs motorcraft plats same that is in the truck and I had new set of coils wich I purchased about a year ago. I put them in and nothing, If anything it seems worse. But Ive yet to trigger my CEL light so Im kinda stumped at this point. Ive done alot of work on vehicles and 120,000 miles Ive never taken my 99 150 5.4 to a garage I had a bad expierence when I was in high school taken my vehicle to a garage and from that point on if I have to buy a tool to do something its worth the knowledge Ill get doing it myself. Now that this got kinda long winded I do appreciate any help I can get to get my truck running like it should thanks for the help.

 

Sorry fastor didnt see your post, I looked at the injectors I really didnt notice anything clogging them is there away to clean them or just buy new ones I do run injector cleaner about every 4-5 fill up so I never really figured is would be an injector at this point Id try anything

 

I would lean towards it beeing an injector as well- It's a strange way for a COP to go bad, but possible if your heater core lines started leaking bad. U changed those so that eliminates that. Run some Sea Foam thru the rail - suck up half a can or so thru your brake booster hose - let it draw that Sea Foam until you notice the motor starting to run different , shut it down let it set for a while (hour or so) fire it up and let it burn out the Bull sh** for awhile. The best way to clean injectors without taking them to be cleaned at a shop. It could be electrical - in the harness or a fuse for that matter - you have a 99 so you don't have the Maxi fuses I don't think, but check the fuses under the hood there one in there that has to do with the ECU , specialy the two on the firewall (those big copper ones) - oh, make sure coil 4 isn't wet on top and you HC feed and return lines arent leaking -any puddles under the truck lately or around your lower manifold? Your plugs- r they 22's - you zapped the pram I take it - reset your comp ? must have ..

 

What is this sea foam stuff I have never done this before I can get this at the parts store?

 

It's the stuff on the left and look it up within these forums for more info if you like - big topic in many threads on here. Your auto parts store should carry this. What I would do is dump a can in your tank before you fill up - fill up w/92 octane. Your next fillup, just use 87oct or whatever you normaly use, then CHANGE your fuel filter... That stuffs great for the injectors but it also cleans the inside of your tank, so don't forget. Still your first measure would be to use a can of it to suck through your system, it cleans your intake and is great for the injectors. This may work or may not depending on the problem. Update the thread when you check the other things and have answeres to the questions asked.

thanks

https://www.f150online.com/galleries...049&anum=10943

 

I will try this, I wont be able to work on my truck till friday night but I will keep you posted. I appreciate the help thanks again , Davis

 

haha i pulled my plugs out and mine have gapped themselves to .06 then again they are white as heck from me being so lean. but i bumped up the fuel with my SCT.. made the truck slower from the injector pulse being so long. but i should be able to bump up the fuel pressure and fix my lean problem without having to cut the timing.

 

What r u running faster, 24's? w/chip - Holey he**, I noticed an exhaust leak on the way home - freakin couldn't be !! Popped the hood and gave it some juice and it sounds like it's comming from under the EGR saucer, lol - Crap!!! think it's plug, I'll let you know later- have tear into er, don't want to belong to that blowout club lol - er-ahhh...pobabley that EGR tube , Yahhh, that's gotta be it, couldn't be a plug got loose..( :