I have a 99 Blazer select 4wd. Once it warms up, it begins to shift hard in gears 1 and 2, if I let off the gas (like im shifting manual) it shifts better. I know my u-joint is bad.....will that cause the rough shifting? I have also been told it may be a dist. cap issue. It seems to have a loss of power and acceleration, not too bad, but I notice it. I have added Lucas to it and have no change. The trans fluid and filter were changed a year ago. Any help would be nice. Thanks.