The way it SHOULD be adjusted takes 2 people.....
You take off the black plastic cover and they are two cables, three if you have cruise control.
There is a big on, this is your throttle cable. A smaller one closer to the engine, this is your speed control. The third is below the throttle cable and has a square connector tab, this is your kickdown cable.
Have your buddy floorboard the throttle and check for slack. There should be NO slack at WOT. If there is, it REALLY needs adjustment. It shouldn't have much slack from approx 3/4 throttle and above. This is where the adjustments need to occur. Proceed below....
You remove the cable by pulling the plastic tab at the end of the cable toward the front of the engine. It'll pop off.
Then you release the two tabs on the square clip and the cable comes out of the bracket.
Once you get the cable out, MARK the cables current position.
Now, there is a little white clip that needs to come off. BE CAREFUL pulling this off, it's what holds the TV cable in adjustment. Don't break it.
Once the white clip is off, the cable is going to try to move rearward, it's spring loaded. This is why you mark the cables position BEFORE pulling the clip off.
Now lookinging into the adjustment housing, you can see some small teeth. These "teeth" are engaged by the white clip. You simply slided the cable forward or backward to adjust it and put the clip back in and reattach the cable.
Each 1/8" movement will raise or lower the shift point ~75 RPM's. Tightening the cable decreases the shift point, loosening the cable increase the shift point.