Hi all,

I am new to the forum, but I am looking for someone with more knowledge than me, wouldn't be that much.

I have a 1999 Ford F-150 2 wheel drive 4.6L Windsor engine.

This truck ran perfect until about 77,000 miles. Well, I think to myself time to chenge the plugs. Wasn't that bad, was a piece of cake, but I got it done. The owners manual called for a 32P on drivers side and a 32 PG on passenger side, I could only find the 32P's so that's what I used.

Truck ran great for a while and then developed a miss on normal slow accelleraction about 50 to 60 mph. Crazy thing did it forever before the engine light kicked on. Turms out I had an intermitant misfire in cycl # 1. I pulled the plug and the porcelin was cracked. Changed just that plug and it ran great for about 800 miles or so, then the miss started again.

Ran with miss for along time again before the engine light came on, this time, intermitant misfire in cyldrs. 1 and 2. Pulled both plugs and the porcelin was cracked again. Changed both plugs and it ran good for a while. Then it started again.

Before going on vacation, I changed all the plugs out with Motorcraft 32P again and the thing logged over 3,500 miles, then the miss started again.

This time I changed to Autolite double plat.s just out of desperation, ran fine for about 800, now the miss is back.

I called the Ford Dealer and explained all this to them and they said they show the truck using an AWSF32FM in both banks.

Before I shell out the money and change again, what in the heck is going on ? Why would the owners manual call for 32P in the Drivers side bank and 32PGs in the passenger side, which just happens to be where cylndrs 1 and 2 are ? Was it a heat range ?

What could be causing the vehicle to keep cracking the porcelin on only cycldrs 1 & 2 ?

Why would Ford now be calling for the AWSF32FM in all eight holes when the owner's manual called for the different plugs.

Please help, a miss drives me nutts and I am tired of buying and changing plugs all the time.

Thanks is advance.

Pete

 

For 2001 I show AGSF-32PM. Maybe over tightening? Manual says 18Nm or 13lb-ft. You might try the engine forums.

 

they came from the factory with the different plugs then they have beed "updated" like 4 or 5 times i think. let the dealer put them in, at least then you will have a warranty.

by the way welcome aboard.

 

Part number has been superceded for service work. The -FM (finewire)is the current and correct plug for the engine and supercedes all the "double-platinum" service replacements.

I'd suggest new plug wires also. Use a generous amount of dielectric grease in the boot.

Steve

 

Just wanted to say thanks to all that offered advice. I found out that something to do with the DIS ignition required a colder plug on the side that keeps cracking plugs.

Steve, you were right on the 32FM being the correct updated plug, perhaps that alone would have cured the problem, however I went with 32FM's on the plugs 1 -4 on the side that kept cracking I went on heat setting colder and installed 22FMs. Truck is running great again, no missing, so now only some miles and time will tell if the FM updated plug and the colder one on the passenger side takes care of the cracking problem.

By the way, when I pulled the passenger bank out, 3 out of 4 plugs had already cracked.

Thanks

Pete