MF I mean the MAF Sensor

How many of you with B2600s have replaced this part? Did you notice any difference such as better gas mileage?

Actually u dont have to replace it unless it fails completely.Take it off and clean it with carb or injector cleaner.U will be surprised at the dirt that runs out and how much better the truck will run.BJ

I think I'll check for vacuum leaks. I believe I read an easy way to check for leaks is to use propane? The idle will jump when the gas is sucked in by a vacuum leak? At one time I connected a vacuum gauge and did all the test outlined in the shop manual. All the readings were within spec. I did clean the MAF with MAF cleaner. I didn't notice any difference. I just think this B2600i should easily get 18 to 19 mpg even with city driving.