i have a 1991 s10 2.5 4cyl 5 speed i keep getting trouble code 25 ATI sensor/high air. i change the MIAT sensor and the air temp sensor and i still get the code. my vacuum motor works above the heat stove but i cant figure it out. its bucks really bad under at about 25mph and i tried to get it smog and its running rich ant the 25mph test but not the 15mph test. can anyone help me?

Does the truck idle rough? If it does you could have a bad MAP sensor. I have 1988 s10 2.5 and it idle rough and coughed and puked. I put a MAP sensor in and it ran better. I had to do the same with my 1994 s10 too.

ill try that