howdy guys fairly new to being a blazer owner but ive got a ton of probs with my 2001 chevy 2dr 4x4, alright i can start it an idols fine as soon as i go to reverse she bogs down ok shift to drive an my rpms shoot up but i have virtually no acceleration when i hammer down my rpms skyrocket but the engine growls an stays pushin only 20 mph im at a loss i love the blazer alot but i cant get a good answer oh yeah and before this happened the other day i fired her up an she shot a god awful amont of black sute outta the muffler onto the ground please help im not spending money till i know the problem please help