I have a 95 Ranger with the 2.3L manual. I have always had problems with the truck pinging with 87 octane cheap or namebrand gas. Usually going up to 89 gets rid of the pinging. It would seem to me that this thing should run fine on 87 Octane like all non-turbo modern cars should. I have a leak in my cat somewhere. Its been a while since I have been under the truck. I can't remember if there is a second O2 sensor on the downstream side of the cat that could be messing things up if there is an air leak.

Perry