Filled up this morning and checked my mpg...17.6 from this tank. Couldnt believe it since I just went back to using 87 octane. Ive been trying to get rid of this spark knocking issue since i bought it so ive been running 93 and sea foam the last two fill ups.

So much better from when I bought it 6 months ago...starting out it was 15.5 mpg consistantly. Only thing I did was change out my spark plugs last weekend.

No real point to this post...just happy with the increase....

 

did you change the plug wires too?

17.6 is pretty good.

 

Not yet..picking up wires and a fuel filter today so I can work on it this weekend. Those old plugs were a B%$^^ to get out. Ended up taking me about 2 hours total.

Ive got about 72000 miles on the truck...not sure if it was necessary to get wires and plugs this early but i think the truck had a hard life before i bought it....lol.Plus if the MPG stays up around 17.5 they will pay for themselves.

 

lol i have 84k miles on my truck and i am on my 3rd or 4th set of plugs, and second set of wires. I bought the JBA Wires. I plan on installing new plugs tonight. They are cheap and not too bad to replace if you do it often.

 

Are the JBA wires better? I just ordered the motorcraft ones. Same with the plugs. Wish i had gotten the platinum ones now. I just got the regular motorcrafts that Advance sells.

 

Motorcraft wires are fine, they came on the truck from Ford so look at it that way...

 

The motorcraft ones are fine. I run their plugs. Either that or the AutoLites, which ever wal-mart carries. They are both made by the same company. They are the best plugs to run on the 4.0

I got the JBA wires for free, so I figured why not use them.

 

thats an awesome improvment from just replacing the spark plugs I think I will do that too now.

 

Well who knows if it will last. I changed the wires and fuel filter tonight. I can feel the difference but the spark knocking has gotten much worse. Luckily I am taking it in to the dealership next week to get it looked at. Its under the extended warranty so hopefully they can fix it.