No there arent. Everything is computer controlled. If there is a sensor that is out of wack the system will detect it and turn the check engine light on. That is the main reason why when you go to Motor Vehicle for an inspection they no longer check the tailpipe. They hook up to the computer and see if there are any faults. Basically if the computer doens see a problem than the car is running as it should and as clean as it should.

The biggest problem with fuel economy is the manufacturer puts a sticker on the window to tell everyone whay the car is capable of. Teh problem with that is nobody will reach these numbers. The way that they come to such a number is with a car on a closed track. For town fuel economy they run a car around a tracl at 40 mph. No a/c, no lights nothing that would create a load. They dont stop and go they just drive. Once they get the mpg they come up with a percentage to make it a more "real life" figure. But its not and everyone is wondering why they cant reach these number.

As common sense as the points i have posted are they are the best chance you will have at bettering the mpg on the truck. I dont know about where you live but here we have 2 types of gas. One is winter fuel and the other is summer fuel. Once the winter fuel comes out there is a drastic decrease in mpg. once we are back on summer fuel it gets better. But there isnt anything we can do about.

The fact of the matter is that if gas wasnt so expensive than nobody would care about there mpg.