recently had check engine light on, flashing then constant, this has happened in past but did not flash that time. first time it went off after 2-3 days, and ran fine while on, during wet highway trip. this time several days after cleaning eng. compt. (hot water, a little soap) had bad misfire w/ flashing light and constant after a few seconds, well it went off, and several days later same incident, (bad misfire, light flashing then steady). changed plugs to bosch 2's 5000 mi. ago, light antisieze on threads, di-electric on boots. thought possible water in spark plug "wells" due to bath. i pulled all the boots, blew 'em out (plug "wells" ) with compressed air and a shot of wd40 to displace any moisture. well it went to dealer today to troubleshoot and they (of course) wanted to change plugs and wires, re-calibrate pcm, and clean maf sensor. the tech thinks that the wd40 caused some arcing and shorted individual plugs causing mis-fire, although it happened prior to me doing that. i had them do the pcm to update some specs(?) and feel i can manage the rest. how long should plug wires last? motorcraft good wires? anyone had problems w/ these plugs? i just saw the maf cleaning post... thanks a million you guys!

 

my original plug wires only lasted like 65k, i replaced them, and haven't had a problem w/ a misfire since then.

 

I recently had a misfire on my '97 4.6. I went to autozone and they told me the code was 304, which is #4 misfire. Two days before I flushed my antifreeze. I put the "t" fitting on the heater hose above the #4 cylinder. Antifeeze had leaked down in side the plug hole and shorted that cylinder. I not saying that antifreeze is in yours, but you just cleaned you motor and I would guess that you got water in one or more plug holes. For that reason I do not spray my engine anymore. I hope this helps.

 

Well, don't pay dealer prices to do plug changes on the 4.6. It may be tough but it can be done by yourself. It wasn't a bad idea to have the PCM flashed incase of newer specs but not absolutely needed.
Yes the Motorcraft wires are decent IMHO. They seem to be much better than a lot of the aftermarket sets out there. I had a set of Xact's made by GP Sorenson only last 22K. On these trucks you should get 50K minimum out of plugs and/or wires, they calim 100K. I also like the Accel, Magnacore ($$$), Talyor, and heard Jacobs are not bad.
As for Bosch plugs it's an opinion game. IMO they are trash in our trucks, I've heard more bad out of them than good (mostly on the +4 series). They seem to run good only in certain cars/trucks and the Triton is not one of them. Best luck I've heard has been with Motorcraft double platinums, NGK, and the Denso Iridiums

 

thanks for the replys guys, will pick up wires and plugs today and keep you posted. by the way, plug wells are dry, and truck runs worse since i picked it up from dealer last night!!! will call them this a.m. after wires etc... thanks again.

 

DO NOT, I repeat "DO NOT GET JACOBS WIRES".
I put the Jacobs Ignition in a couple of years ago and it came with their wires. I stayed with them just because I thought THEY HAD TO BE GOOD----RIGHT----WRONG!!!
Let me tell you they were JUNK. They would not stay on and they misfired to the block for who knows how long.
I recently went with Taylor Spiro Pro wires and they are excellent. I had immediate improvement in acceleration. Also, it has been a while since the engine has run this smooth.
These wires are pricey but so are all the good wires out there. The wires fit into the original wire looms and go on with a positive click.
Taylor wires are VERY NICE and definitely worth the money.
I will also recommend Autolite Platinum (not Duel Platinum). This is because they are easy to gap and install and also because I don't think any plug should be left in for more then 25,000 miles.
I change my plugs at 20,000 miles on average and have found significant wear. Save yourself some money.

 

OK, I stand corrected. Jacobs are junk wires.
I usually try to tackle the plugs when they reach about 35-40K on them. It usually doesn't happen until I'm over that mark and can feel a misfire. Basically I'm the opposite of WLF, I leave them in longer so I would go with a double platinum.
If that's a 4.6 and as we all know has DIS ignition, which is also called a wasted sprak system. The reason why is that for every spark on the intake/power stroke, the opposing cylinder is also firing it's just on the exhuast stroke. The weird thing is, is that it fires backwards, meaning it fires from the tip (ground electrode) to the center electrode. Using a double platinum plug has the platinum on the tip which will help prevent wear in this case.
Now WLF has the Jacobs (Mileage Master?)ignition setup which most aftermarket ignitions recommend using a standard copper core plug and to change them fairly often. WLF please correct me if I'm wrong, I haven't studied the Jacobs setup that well.

 

KY

My 4.6L is coil-on-plug, not EDIS. I'm going to change at 60k, when it's in for the big PITA service.

 

KYFordFreak,
I actually have the DIS electronic ignition from Jacobs but it is essentially the same thing. It provides a multi spark fire on each cycle.
Now I too have been told of this FIRING BACKWARDS ignition but can't for the life of me understand how the electrical charge can go TOWARDS the coils. I think these ignitions and plugs fire like any other, from the center electrode to the outer arm. Perhaps there is a x-tra spark on the exhaust stroke, I don't know. I do know Ford used different plugs on different sides of the engines to try to archive the 100,000 mile tune up, but I think they used different heat range plugs to compensate for some difference in temps.
Jacobs now says it is ok to use Platinum plugs with their ignitions. The reason I use single platinum is because they last as long as I need them to for a fraction of the cost. Having the platinum on the center electrode makes since as there is a much smaller wear area. The arm however has plenty of area and usually does not wear down on ANY plug. The wear you see (and can measure) is almost always on the center electrode.

cpadpl,
If I had coil on plug then I think I would change them like you. Only when I need too. That sounds like a real PIA.

 

I know it all sounds wierd but that's the way I was told by a GP Sorenson (large maker of caps, rotors, sensors, coils, wires, etc) tech trainer.
I'm pretty sure the two different plugs of the OE setup are the same heat range. I was told the difference was that some had center electrodes with platinum and the others had the platinum on the ground electrode. So that makes the OE plugs single platinums, which would be cheaper than double on the assembly line. It also helps to suppost the theory that they do fire backwards. The trainer did say the ones that fire backwards on exhaust stroke, still fire backwards on power stroke.
I agree if your going to change them often single platinum or even regular copper core plugs would be fine. I also agree that 98% of the wear is on the center elctrode
Yeah I knew the newer 4.6's had the COP system. I have to agree that would not be fun. I do not look foward to my future truck if I buy Ford again, as I plan on getting the 5.4.

I think we need an expert in here!