Hello all this is my first post so forgive me if it's already been discussed. I have a 1989 Comanche Eliminator with approx 230K miles. It leaks oil but was running like a champ. A few days ago I was traveling down the road and truck started losing power. I had to turn around and get it back to the house, When I was able to pull into the driveway the truck would barely pull itself. It went form running great to backfiring and sputtering. Backfire sounded as if it was coming through the air filter. If the truck is at idle it still runs ok but but when I put it in gear the rpm's drop and starts missing again. I've changed the fuel filter and repaired a broken vacuum line that I wasn't aware. Now the truck is running better but still won't pull itself. I don't know if it possibly the catalytic converter or if a sensor is bad. Has anyone experienced this before and if so what was the fix. Thanks