I have a 91 RS 3.1 TPI that has developed this problem it will ocassionally lose power and start backfiring. Had a similar problem about a month or two ago seemed only to happen after filling gas tank. Changed fuel filter and was fine until a couple days ago. Should I change filter again or start looking at something else. Any help would be appreciated.

 

Sounds like your fuel pump is about to take a nose dive.

The in tank pump is cooled by the gas around it and running through it. If you have an older pump and you run the gas level down to E, it'll get hot and start to seize. Once you wait awhile for the pump to cool it'll run fine again. Once in a while the pump will get weak and the car will cough and sputter like a backfire when it's really starving for gas. If it does it while you're driving the car it'll seem way down on power. Eventually it'll go out completely and there you'll sit.

If you've never swapped the pump, it's going to need it eventually, might as well get it over with.