Improved mpg after long trailer haul

[crunchie_frog]

I recently pulled a ~ 3,000 lb trailer about 400 miles at interstate+ speeds. Of course, it drank the gas at about 10 mpg (1999 v8 AWD, 170 k miles) during the haul. Afterwards, my average mpg on my normal daily driving route has increased ~1.5 mpg (14.7 to 16.2) I have measured this on my in vehicle computer and manually at gas refills. I am just guessing I "cleaned" something out (fuel injectors, intake or exhaust valves, O2 sensors or catalytic converter) while under the heavy load pulling the trailer.

Anyone else had a similar experience or an idea of why my mileage increased significantly?

I love these v8 Exploders, they just keep going and going and going...

 

[Flash]

2 things.

1. The highway trip probably cleaned some carbon out of your heads and pipes.
2. You may have consciously or unconsciously adjusted your driving style for torque without overstraining the engine while towing. Driving this way when not towing is very economical.

 

[SoNic67]

Or maybe... it just warmed out outside

 

[BustedKnuckles24]

You did an 'Italian Tune-up'. Driving it hard like that helps blow out carbon build-up and maybe even cleaned out the injectors with extra fuel flow when pulling the trailer. I like to get it out on the highway occasionally and drive mine in lower gears to run higher rpms than normal for a bit to do just what you did. I've long considered it beneficial.

 

[crunchie_frog]

You did an 'Italian Tune-up'. Driving it hard like that helps blow out carbon build-up and maybe even cleaned out the injectors with extra fuel flow when pulling the trailer. I like to get it out on the highway occasionally and drive mine in lower gears to run higher rpms than normal for a bit to do just what you did. I've long considered it beneficial.

That is what I am thinking too, seems like a relatively cheap, effective tune up to me.

 

[alohamonte]

If that was beneficial, you might consider a little more cleaning - fuel additive in the tank, sea foam the intake, clean the TB and MAF...