Denso Iridium TT Spark Plugs. Update on gas mileage.

Ok, like I said in my other post on these spark plugs, I just got in from a 605.7 mile trip from the Des Moines, IA area to Memphis, TN area. I averaged 18.2 mpg with these plugs. Up from an average of 16 mpg before.

Now someone said that I had done a lot of upgrades on my truck, so the increase in mileage couldn't be attributed to the plugs alone. Others said you only get higher life span with iridium plugs, and no increase in mileage. I have no clue what type of mileage anyone gets with other types of iridium plugs, but these are my results with the Denso Twin Tip plugs. They call them the Denso TT Plugs.

Let me set the record straight on what I have done to my truck. I put in a stock style K&N air filter back in September with approx 1300 miles on the truck. I saw no increase at all in mileage. Absolute nothing. I posted that I did feel a better throttle response and it sounds better. I know a lot of you don't like K&N and that's ok. Don't want to rehash that. To each his own.

I also did the anytime fog light mod. And of course all of you know that has absolutely nothing to do with mileage.

And last of all, a couple of weeks ago, I put in the Denso Iridium Twin Tip plugs, took a trip and got 18.6 mpg. Sure it was not a long trip, just 116 miles or so, but as I posted, I have never, EVER gotten better than 16.8 mpg on my truck, and that 16.8 was a one time deal. Never saw it that high again. Ever. The average mileage on my little truck was always around 15.9 to 16.1 mpg, under every "normal" type of city or highway driving. I did get a 14.9 once with purely city driving, not driving much over 40 mph that entire month, lot of stop and go, short trips, things like that. But that was the lowest ever and only once did that happen. I think I did go do some dirt road driving on that tank of gas and of course, I goosed it, a time or two, lol.

So on this trip, I filled it up and the starting mileage on the odometer was 7956. I did use the trip meter to get it to the tenth of a mile. I drove 153.8 miles to Keokuk, MO and it took 8.6 gallons to fill it back up. That was 17.9 mpg. (On a side note, the gallons was actually 8.55 exactly and that would give it 17.98, rounded up would be 18 mpg, but I rounded up everything above 0.5 to a 1. So 8.55 rounds up to 8.6, giving it a 17.9 instead of 18, which it was if I rounded to the hundredth instead of the tenth.)

I drove on 166.0 miles to St. Louis, MO and it took 9.2 gallons to fill back up. That was 18.0 mpg.

Drove on 285.9 miles to Memphis, TN and it took 15.5 gallons to fill back up. That was 18.5 mpg. Ending mileage was 8562.

So on a trip of 605.7 miles, total gallons was 33.3, giving an average of 18.2 mpg. This was all highway driving. I took photos of the gas receipts and photos of the odometer. But I guess if this is not proof enough, no photo will change anyone's mind.

I was planning on taking another 600 mile round trip to Alabama this week but that was canceled, so the only other long trip I'll make over the next three months is back up to Iowa next week. I'll check that too. But I'm sure it will be the same. Say what you want about this plug or that one, these are actual results on a decently long trip with legs of 153.8 to 289.5 miles, and I'm getting the same results. A 2+ mpg increase in mileage.

I have no idea if I would have got the same results with the stock air filter being left in before I changed it over to the K&N. But like I said, I did that way back in September last year and saw zero increase in mileage, so I have to attribute this increase to the plugs. It was an instant increase from the day I put them in the truck just a few weeks ago.

Best of luck to you guys if you try them too. My truck is a 2015 4x4 V6 auto, double cab with the Off Road package. It has the rugged terrain tires on it. All stock. Tire size is the 16" 265, not the 245.