hey guys I've got a 91 blazer with a 2.8 ,5 speed and lately i'll start it up and it warms up and all but as soon as i start driving it will rev up to about 2500 and stay there the whole time i'm driving from time to time it will come back down but mostly stays revving high and suggestion? or what i could do to fix this problem, thanks alot appreciate any feedback

 

Is the throttle cable sticking?
Under the hoood can you open and close the throttle? It may be the malfunctioning throttle position sensor.

 

thanks for replying but no the cable isnt sticking I thought that at first and i even took the cable off and started the truck and still it was revving high after i just got back from driving all day

 

I'm not sure if the '91 2.8L has an IAC valve, but if so, it may be malfunctioning. It may just be time to pull the throttle body off and give it a thorough cleaning.