Chevrolet Repair: Chevy Truck loses power on highway hills, chevy truck, cat converter

Question
1995 5.7L V8.
Runs fine on the highway. Gets up to 75 quite easily.
At 75mph, if you start going up a hill, the speed drops by about 10 mph and the accelerator does not seem to be able to engage.
RPM's stay about 2,000
Any ideas what could cause this to lose power going up highway hills?

Answer
Hi Barry... check to see if you have a plugged cat converter, if thats ok install a scan tool and see if your trans is shifting down when you accellerate or staying in OD. try shifting down manually and see if that makes a differance. check codes and correct any found...hope this helps