Transmission runs rough at above 70

[Robailey77]

I have a 1998 chevy k1500 and the tranny, which is fairly new, seems to run rough when over 70. When you get to 67-69mph it seems like it smooths out as long as you aren't on the gas. Was wondering if tires might have anything to do with this as my tires are not good at all. Very uneven wear

[txab]

Tires is where I'd start. Then drive shaft issues

[Robailey77]

Thank you greatly. I am looking at tires now. I have another thread asking about tire sizing

[1997SierraSLT]

turned out to be an MAP sensor on my truck. The ECM will not throw a code.

[Robailey77]

What is a MAP sensor?

[txab]

What is a MAP sensor?

 

http://lmgtfy.com/?q=MAP+Sensor

[Robailey77]

Thanks man I already did that. Very intelligent though.