I have an 88 auto as well, I really like my truck. Are you throwing any codes? Your Ranger has 2 fuel pumps. I think they started doing that in 88, maybe in 87. You have a towing fuel pump in the gas tank, a high pressure fuel pump on the drivers side frame and a fuel pressure regulator on the drivers side by the firewall on the frame. When you turn your key on you should be able to hear the fuel pump slightly in the cab. It could be a number of things, if it were throwing a code, it would be much easier to find out what's wrong. Do you have any white smoke coming out? My 88 heads were screwed when I rebuild my engine @ 98,000 miles. It could be a contributer to the problem, but you would know if your heads were cracked (mysterious loss of water, water in oil, greenish/yellow sludge under oil cap and or under valve covers). You're gonna have to really do some poking around to find that problem.