I have a 93 s10 Blazer, 4door 4wd, 4.3 litre. When in OD, it seems to lose power on hills, and seems to not downshift till I kick it a bit. Then it will pull the hill at about 2500rpms. Doesn't seem to shift hard when it does shift, though.
Seems to be fine in D, and climbs hills like a raped ape in the mountains. Doesn't overheat. Oil pressure good.
I changed the CPI unit (it was going bad), and changed tranny filter and fluid and added lucas tranny fix, and it is still doing it. Could it be a vacuum issue? I can hear a vacuum hiss in my heater controls. Any ideas??
I am new here, and apologize if this has been covered elsewhere...couldn't find it if it was.