Since I'm new to this forum just wanted to post a couple variables in MPG on my 2022 FX4 King Ranch 5.0. Just bought it at 58,000 miles with the original plugs still installed. I tested it several times in very similar conditions and it averaged 16.8-17.6 on the same exact route on ECO mode.
I changed plugs the other day and gapped at .040 using OEM plugs. I let them seat in for a couple days and did the same test of about 14-15 miles same route with a full tank each time and the MPG averaged 18.3 to 19.7 after 2 tests. I would have to say that's a reliable increase to 4+ year old OEM plugs, I changed them at 61,500 miles.

 

How long were your test runs? Hand-calc or did you just grab the numbers from the Lie-O-Meter?

 

x2

 

From the Lie-Ometer, Hilarious response but that's all I use. Not an exact science, just conveint, LOL

 

A 14 to 15 mile test run isn’t anywhere far enough to make any kind of conclusion. Unless your spark plugs were bad I doubt it had that big of an impact.

 

my old plugs were burnt and the electrodes were worn making the gap on each plug about .053 to .055. It was time.

 

seems like you don’t want to answer/address the questions about sample sizes used for your stated mpg stats.

 

the sample size is good enough since I make that trip daily at least 2 times a day. All the conditions are consistent day to day. Does that count as an answer? Just having fun with my new ride. Peace

 

doesn’t answer the question.

 

it is a small sample size compared to professional labs. To me I’m not avoiding the question. Just a novice at these things. When I was in my early 20’s I used a calculator ant the pump receipt to divide the miles driven by the gallons used. I figure the lie ometer is probably more accurate than the old fashioned way.

Anyway, everything is based on averages, no biggie!