My 2000 LS 4X4 blazer has 97500 miles on it. It has run very good so far, I have underdrive pulleys for the crank and alternator, cold air intake and a magnaflow exhaust. These mods have been on the rig for about 4 years my highway mileage was about 23mpg hwy/ 17 city.
In the last4 months my hwy mileage has dropped to about 17, city about 14. There are no check engine lights and the idle is still about 650 rpm, the engine still feels strong with no hesitation. The fuel pump was replaced in December, about a month after my mileage dropped noticeably. I am lost for the reason why mileage has dropped so significantly. Any thoughts would be appreciated. thanks
Al

 

97,500 miles.
Tune up time= plugs, wires, distributor rotor and cap, and fuel filter.

 

Yeah I would say tune up time. That helped my mileage out.

Also this section of the forum is for introducing yourself and your blazer. This would get more response if put in the General Tech section.

 

I too would say that it is time for a good tune up consisting of plugs, wires, cap and rotor. Cleaning the MAF sensor and the EGR valve would probably be beneficial as well.

*Moving to 2nd Gen Tech*

 

first- welcome to forum
next-change air filter, let some air in that motor