I own a 2001 2wd 2 door blazer. I recently purchased the vehicle and right after purchase had some problems starting which resulted in the shop replacing the fuel relay and fuel pump. I did not own the car long enough to know what the miles per gallon were before the work was done but I have noticed now that I am getting between 15- 16.5 miles per gallon all high way driving. I commute daily from NH to Boston. Can anyone tell me what the problem may be since I have read that the 2wd 2 door should get about 16-17 city and 22- 24 highway. Also is there anything mechanical that can be done to improve MPG. I have mixed reports about adding a K&N air filter. would this help? Please help. I appreciate all the help everyone has given on this site. Thanks
Mike

I had a simliar problem about a week ago. only with a 93 blazer,
and I was only getting 10mpg highway!!!

It turned out the previous owner put the wrong type of cheap spark plugs in and 4 on them were fouled(1 was extremely bad), and all of them were timed wrong.

New plugs new wires now it gets better mileage (not sure of highway mileage yet havnt been able to test it). And I have better big hill climbing power now

This is close to typical for these vehicles, especially in cold weather. As the temperatures drop, the computer, in response to the lower temperatures, will add fuel to the mixture. These vehicles are very heavy, close to 4,000 lbs, empty. They will use fuel regardless of how they are driven. Ray

are you talking about the 4.3 V6 engine?
I have a 1993 4.3 and it is having problems with running rich and therefore gas milage is down to 14-15 or so...How long have you had your truck?

A Tuneup May Help Plugs-wires-o2 Sensor Sinthetic Oil

get a throttle body spacer, better fuel econ. and more mid range power. it spins the air passing thru the throttle body going into the combustion chamber. i am ordering one from summitracing.com