So if I haven't ran my 99 blazer LT in a day or two it has trouble starting takes a couple of turns, then recently started hearing a hissing sounds coming from the muffler. i did hook up a scanner to the blazer and it was saying it is running to rich so I did a full tune up on it. including a new fuel filter. It also is not got a lot of power when I am getting on the highway or speeding up on the highway like it should. Plus my gas mileage is down from what it should be after I changed the fuel filter it jumped to 18-19 mpg then once I heard the hissing sound it is back to 14 mpg. when is has trouble starting and when it does it runs really rough I push on the gas pedal and it doesn't rev up like it should and it sputters bad. I took it to a friend that knows a lot about cars and he thought the noise sounds very unusual. I was told it could be many things. i think it may have a small leak in the exhaust and bad o2 sensor but would like to know for sure what it could be or is.


Has a cold air intake, replaced the EGR VALVE, AND NEW PLUGS WIRES, CAP, ROUTER, FUEL FILTER???

 

Hi mnwild88,

So what ever happened with your Blazer? I'm thinking some onboard processing unit was the source of the problem.

I recently inherited a dead 1999 Blazer LT and spent $4700 to revive it. It is very clean and has 45k orginal miles. Hopefully is will run okay for a long time.