Okay lads, got me a 99 blazer 4x4 other day the trailblazer edition, not that its gonna be blazing any trails at the rate its going but it has issues, blinking ses light when i put it in drive and codes are p0300 and another code for a o2 sensor but i mean for gods sakes?!?! Are these 4.3s this bad on gas just with a random misfire code, it runs okay, doesent stall or anything and has plenty of power, am i missing something. 10 gallons of gas took me merely 50 miles?????? I'm about to drive the damn thing across the scales at the salvage yard and call it a day. Even though its in perfect condition ?? Talk to me somebody, I'm use to driving my corolla and going 100 plus miles with no gas

 

Welcome from Florida. Sounds like it is running rich. Is there a lot of black smoke coming from the exhaust? How many miles are on it? When was the last time it was tuned up? I have had several of the 4.3 V6 blazers and S10's and the worst I ever got was around 13 mpg.