I have an 04 blazer 4 door with an automatic trans. I have given it a tune up (plugs wires oil ect) a new radiator and thermostat within the past 4 months or so. Right now I'm having an issue when I'm taking off with the engine warm it'll stay in 1st gear at 5k rpm until I let off the gas, then it shifts. What could this be? It shifts just fine normally unless I have the pedal floored in 1st gear (D). Any help would be much appreciated.

 

Keeping it simple, check the level of your tranny fluid. A low fluid level can cause a few different problems that you might think are caused by something else.

 

Ok sorry about the late update since my last post I've topped all fluids including the teams but I've noticed the exhaust has gotten a lot quieter and when you get the engine up to about 4k rpm it makes a weird almost grinding noise that was coming from the lower part of the motor. I was thinking maybe it is something horribly internally wrong I was also thinking the cats may have gotten plugged up. Any help would be greatly appreciated.