i got an 01 blazer with about 111k on it a few months ago i noticed there is this noise comeing from what sound to be like from the back of the motor near where the injectors go you hear when you accelarate mostly but you can slighly hear it when its at idle i just had the injectors replaced about 4 months ago so they are farely new it dont sound like a valve tap either is more towards a chatter sound and i need your help also today i noticed speeds above 60mph it feels like a flat tire but not as bad it almost seems like there is a big screew or something in it but i checked and nothing any help would be awsome thanks