I have a 94 ford ranger pickup that I bought about two years ago knowing that it was on its second transmission but had been otherwise well maintained. When I first bought it ran well, but soon it developed a slight problem where when it was really struggling up a hill, it would kind of rattle. Over time this rattling has gotten worse until now it is happening all the time. The other symptom that’s happening now is that when the rattling happens consistently for a while, the truck will overheat. I have an appointment to go to a mechanic on friday, but I will be taking the bus to work until then and really need this fixed. So is it something simple that I could fix?
It sounds to me like you are experiencing severe spark knock.
The solutions could include new plugs, or cleaning carbon out of the cylinders, or perhaps cleaning/replacing the EGR. In the short-term, switching to premium gas may resolve the problem, but you really should fix the underlying cause.
Years ago, you could retard the timing slightly, but I don’t know if this is even possible on your vehicle. If it is possible, just be aware that retarding the timing will lead to less power AND lower gas mileage.