I have a 86 Convertible with a 3.8L in it. It will crank up just fine and run for a little bit then will die out. The injectors look to be shooting the fuel in just fine. I have not been able to find any vacuum line leaks. Before I replace the carb what else should I look at?
There are not many around here with a 3.8 in a stang, and I think they came in rangers too, I can say that it will have injectors, probably CFI, or a carb, not sure about when they changed, if, like you say they appear to be putting fuel out I would say check the ignition, give it a shot of starting fluid and if it does not fire you have an ignition problem. It don't take much, just a quick shot, see if it tries to start.
The ignition switch under the dash is a known issue with these cars too.