my wifes 04 trailblazer will rev high at about 20 mph and does not want to shift unless i get on it a lil harder. also when it does this the rpms shoot to about 4000 or better. help please and thank you.
First check the transmission fluid,if it is good may not hurt to change the transmission filter and fluid,if this dosnt help may need a tranny before long.
Smell the fluid,if it has a burnt smell,you need a tranny.
Your RPM issue may be the idle air control sensor.
Rowefast would that effect the shifting while you're driving?
Yes, having high rpms affect your shifting, the computer is tied into the operation of the trany, so with the motor running fast, that needs to be corrected before assuming anything with the trany. Its like having your lead foot to the floor.