Ok i had the trans rebuilt in my blazer. since i got it back it has not acted right. if you came to an almost stop and then accelerated it would jerk and shudder. I took it back. they said they fixed it. got it back and it had a jerking vibration between 45- 55 mph. i thought it was the torque converter. i took it back again. they call and say they put in a new converter i pick it up. same thing still happening along with the stop and go issue. i take it back yet again.
he says they ran a computer scan and that the knock sensor was picking up something and causing the timing to retard, but that it wasnt bad enough to tell what it is.
it does seem like it is down on power some.
question is could this be the problem or could the knock sensor be bad. the blazer seems to run fine other than these issues. you can't hear any knocking or ticking at all.
any suggestions?

blazer is a 95.