I have a 04 Mazda tribute with 267k miles 3.0 v6, basically when I'm driving the throttle seems to get stuck and I can actually take my foot off the gas and the car will continue to stay at that speed, other times when I'm stopped at idle speeds it will completely bog down to around 500 rmp and want to die.
I've changed the tps and IAC value last week and the problem is still happening, any info would be great.

 

Sounds like two problems, first sounds like a sticking throttle cable or throttle valve, second might be an air leak into the manifold after the throttle valve.

 

Have you cleaned your throttle body?