I have a 2003 4 X 4 Dakota that was getting 14 mpg and had 60,000 miles on it. Changed the spark plugs and that has dropped to 10 mpg. Not being a mechanic, I took it to a reputable service center and had new plugs installed with no improvement in mpg. Trip center says 10 mpg average and comparing that to miles traveled vs. miles to empty it is very close to 10 mpg. No miss, plenty of power. Any suggestions?

 

what type of plugs they put in it?

 

I'm guessing the put platnum plugs in it. I would put champions or NGK in it and see if that makes a difference. also did you cange cap/rotor, wires?

 

i have a 2000 dakota sport with the 4.7 and i installed some autolites 3923 w/ new wires. runs great!

 

new wires? the 4.7s don't have plug wires..just coils and copper wiring.

Anyway...I put champions in. I don't have much of an improvement...tho it's hard to tell in the winter with morning warm-ups and heater always on.

 

i have a 05 4.7 and was getting 20/22 on the highway and 18/19 around town. went with the platnum plug and it was a mistake. lost an ave. of 45/50 miles to a tank of gas. went back to the stock champion plug and mileage went back up. they also say the 3923 is a cooler plug and the 4.7 likes this

 

I have NGK v-power in mine and I love them

 

I have Bosch Platniums and I have never ever thought about the differences in plugs. This week I am switching from Bosch to NGK V-Power. Maybe I can get better MPG.

 

i was getting around 15 mpg. i drive mostly city and have a lead foot. i just put in the NGK V's .I'll let y'all know

 

Champion plugs I beleive. The mechanic was not in favor of autolite, but not sure if that was what I had installed. Still no improvement, have about 5/8 tank of gas and info center says I will get 112 miles out of it. Possible Oxygen Sensor problem? Hope not as they are not cheap.

Thanks for all the input.