So,this is my son's Trailblazer....it went into reduced engine power one day on his way home from work and barely made it to my house.Plugged in my scanner and came up with P1512,P1515 & P1516.A friend of ours,after checking out You Tube installed a new throttle body,no change.It still has an erratic idle...goes up and down from 500rpm to about 2000rpm.Re-installed the old one and returned the new one.For some reason it got better and now only has a P1512 code.Did a idle relearn procedure but not sure if I did it right,no change.Both O2s acting funny so replaced them,no change.Tugged on the wires at the connector,no change.They seem fine.One odd thing though,the actual throttle position is at 22 and the throttle position desire changes as it should.Also when stepping on the gas pedal shouldn't the throttle blade move accordingly? It is fixed closed.
Any Ideas? I'm thinking of getting another throttle body.
Posted here because I saw nowhere else to post it.