I recently bought a 1987 Toyota 4WD Pickup. I have one problem and another question. Okay , my problem is when I am going up a hill while shifting from third to fourth, or fourth to fifth I can press the accelerator just about down to the floor and it stutters. What could be wrong there? And my other question is, What would be the Cheapest way to add a little or a lot of horsepower to it?