shaking seems to be more prominent in park rather than in drive. seems like it skips a beat every few secs in drive

 

i have calculated the mileage the old fashioned way with a calculator. three fill-ups and it is the same. i dont trust the trucks.

i have used seafoam treatment. and i use that lucas stuff(probably snake oil) ill get an alignment and see if that changes. just wondering if anyone else tried the E3's

 

I listened to the guys that had tried it, and used the Autolite plugs last time I changed them (59,000). I was not unhappy with the Champions, which had been in since 27,000) as I had gotten up to 19 mpg on the road with them. My in town mileage varies from 13.99 to slightly less that 15. Turn on the air, and that can go down a mile or two. Anyhow, after installing the Autolites I got 20.97 mpg on a trip to Wyoming. This was mostly flat ground, but driving 75-80 mph (posted limit is 75 there).

One thing I have found with this truck, as I have found with others before it, is that each of them seemed to perform better on a certain brand of fuel. Mine seems to prefer Chevron or Shell over everything else. On the road, I have gotten some of my best mileage from the cheapo Pilot truck stop gas. California's "green=crap" fuel gives consistently worse mileage than out of state gas.

 

chevron and shell have the cleaning agents in their gas though

 

i guess...i've heard seafoam works well...just gotta try it when i get home!

 

I too experience the same issue. For me it is a little different. When the temps are warm I get 17 MPG consistent in town and a solid 21MPG sometimes 22 for long trips. When cold weather arrives I get between 14.8-15.5 MPG. The other difference is I have the 3.7L. It has all its regular maintenance with all synthetic fluids. I use the standard NGK plug that the 3.7 calls for as it seems to run best with those.

The funny thing for me is that you guys all get the same mileage with the 4.7. I should have got a V8! Of course that does not help with your problem but I have had the same thing happen for five years straight now. My truck just turned 58,000 miles.

 

Seafoam works great, only thing is it makes one hell of a smoke show first time you use it. I'm also a member of a jeep board and there is a theard that is about 20 some pages long all of guys that used it and loved it.

 

When the winter comes add crap to gas for winter driving which brings down mpg's

 

I never got more than 15.5 mpg with my v6 Highway or city, but i was also auto and 4x4. That said, just before i got in the wreck, i had just cleaned my air filter (KandN in factory box) and put some lucas's fuel injector cleaner (fuel additive) in mine, and it showed 16 on the overhead. It was just rollin arround to time for a tune up, and oil change.

 

my ? is where is the best place on the V8 trucks to use the seafoam? throught the brake booster or the PCV valve line? and where is the brake booster line located? i dont have my truck to go look at and want to know so when i get home and its freezing ***** outside i know!