Bob Vaughn wrote:
I purchased a 2013 GMC 3500 with a duramax diesel engine.....I filled it up, took it on a road trip down the interstate 65 miles to the next town then turned around came back and refilled it. 17.3 mpg.....so I installed a K & N filter expecting to better my mpg......Wrong answer my milage went down 3-5 miles per gallon. I wonder if I was expecting too much to even main tain the milage.....what went wrong? could the gas station fuel pump been wrong?
Bob - I hope you get some actual useful feedback in this thread from people who have actually used these products on diesel engines such as yours and can report back
first-hand.
I have used K&N panel filters in all my gas vehicles for the past, I don't know, maybe 24 years and have not had any problems. From Korean cars, to my Audi to my Sierra. No problems. No issues with "extra dirt", no issues with oil fouling the MAF sensor, etc. You have to know what it is and how to use it properly, that is all.
What I did not see in all the years of using these is any appreciable change (
gain or loss) in fuel economy. In my experience it does not change that. A chip / tune does a much better job in that regard.
Everything else being equal between your test runs, I think that dropping 3-5 mpg from 17.3 mpg is unusual. I would guess that the ECU has not had sufficient time to recalibrate yet.
