Hey guy's, I have a Factory Tech Valve Body installed (No Chip is installed at this time) and when I start off in first gear at light throttle, the transmission shifts okay.

However when I start off and go with 1/3 throttle, the transmission holds First gear to long and will not shift, unless I let up off the accelerator a little, for it to shift.

Cannot figure what the problem can be, other than the fact , the Solenoid Pack needs to be replaced in this 99 Lightning! Any and all ideas or experiences would be appreciated, as to what my problem might be. Thanks.