Autolite does indeed make Ford plugs, but they make them according to Ford specs. What that means, as far as I know, is that Ford's quality control standards are a bit stricter than Autolite's when it comes to Motorcraft spark plugs.

The way I look at the spark plug debate is as follows: if I use Motorcrafts, I won't have any plug-related problems in my Fords. If I use another brand of spark plug, I might. So it all seems pretty straightforward to me...

 

My wifes old 96 Explorer 4.0 had 136000 before I changed the plugs with no re-gap and honestly really didn't look all that bad

 

Hello, I have an 01 4.0 ranger. I belive it has the bosch +4. The engine is very weak. What model or PN do you all run on the motorcraft.

 

AGSF34FP

http://www.motorcraft.com/catalog.do

 

Just my 2 cents, I replaced my motocraft at about 48K for the Bosch +2. It ran better for about two weeks and then I noticed my gas mileage take a dump, like 3 mpg. I replaced them with champions, 12 months later I’m still getting better mileage, but I can recently feel loss in power, not necessarily the plugs though.

 

Just thought I'd be fair and post up my intentions. As of right now I don't have the time or spare coin to do this plug swap. When I do get around to it though.. I will give this a try and post the results. Just don't look for it soon.

Rich

 

i don't have experience with trying different plugs in the 4.0... but in the 95 mustang gt i had it performed way better after i swapped out the platinum plugs i had in it for conventional plugs... in my opinion alot of the gains u hear about platinum plugs is because the plugs needed to be replaced regardless... don't quote me on this but i believe the same thing happens with u install platinum plugs in the 4.6

 

I am going to go with NGK Iridium because of how hard the 4.0 SOHC plugs are to change. I use them in everything, and for once the hype was worth it and they are priced right $6.99 a piece locally. I've tried EVERTHING, and I beleive that either Motorcraft or NGK are the way to go.

 

Just so you know I have tried the Bosch +2 and after two weeks my gas mileage dropped by about 3mpg, pulled the plugs and the tiny center electrode was all but gone. Why the hell do they put two ground electrodes and a smaller than normal center electrode on these? Just my 2 cents.