blue notch

I have seen several post on here about some trucks gas mileage falling off a liitle bit, and some of you have replied that the spark plugs seem to be the problem,does changing the plugs seem to be the fix if any of you have done this, Let me know what you think of this. My truck seems to have dropped a few mpg's as of lately.--Thanks

blue notch

anybody?

kookookachew

Well, I changed my plugs but haven't been able to compare my before and after mpgs yet. It would make since though that changing the plugs would increase fuel efficiency, a stronger spark makes for a more efficient burn.

Its always a good idea to due routine maintenance on your vehicle, if your in doubt, change it out.

Fx-all-4-me

It could def be a possibility, but i would recommend checking your air filter, and tire pressure. in a stock rig that is the main cause of fuel efficiency loss.

tleach17

I changed my plugs at 100k like ford recommends and my mileage did not change. But im still glad i did it.

Steinmetz

Changed mine at 132k, truck has Autolites in it and was hesitating and idling like it was running on 4 cylinders. saw a significant change in gas mileage and power, but gas mileage has somehow gone back down and performance,and the truck has 133700 WTF.......

sped79

Might try your fuel filter if it hasn't been changed recently. Mine was having same symptoms and that cured me. $10 and five min. well spent.

BTW anyone have any experience with changing the spark plugs on they're 5.4? I've heard it's tricky... especially with Ford's stellar head/spark plug issue. I would love some insight or tips before I give it a shot.

seraphim

Any recommendations on particular spark plugs? Looking all over ebay and I'd like to know which ones you guys think are good, and which are crap.

jensen41455

I think the biggest thing is having a quality torque wrench. You don't want to strip those threads out, but you want the plug to be tight. I think the main problem is mechanics doing a plug change and not getting them tight enough. They then back out and starting vibrating up and down wearing out the threads. I went down to the dealer and looked at my head and it was a smooth bore all the way down the hole except for the very top thread. You could see where it had been ripped out on the top thread when it ejected from the cylinder.

Steinmetz

It's a good possibility of the fuel filter being clogged, don't remeber if its ever been changed...as far as plugs in a 5.4, Motorcraft is the way to go and I would save yourself the headache and have someone else do it.