Hi I have a 2000 Chevy Blazer 2 door 2 wheel drive V6. My proplem is that when i accelerate it hesitates or bogges down and no matter what let off the gas or not it just takes its time getting up to speed. When i am already at a descent speed and i punch it it revs up but little go and once in awhile i can here it backfire under the hood and it seems like it doesnt shift as soon as it is suppose to or it shifts to soon. So anyone with a thought on this it would be much appreciated. Thanks