I'm new to your forum. I'm working on a friend's 1997 F250 HD 4x4 auto long bed with two fuel tanks. It's got the 7.5l/460 cu. in. V8. It's fuel injected but with a distributor. Unable to find a Data Link (16 pin ) connector in passenger compartment, but did find a data connector under the hood on driver side near air filter and hooked up scan tool--no codes, since battery had been disconnected.

Problem: Truck has been sitting for 6 months or so. It was running fine but now it's blowing fuel and possibly water (coolant?) out the tail pipe. Very heavy fuel smell from exhaust. Cat is dripping fuel. Haven't checked compression yet but will be next. Assume it's a blown head gasket Replaced fuel pressure regulator, but no change. Old FPR held vacuum OK. All injectors firing based on stethoscope check. Owner says it couldn't be head gasket. It was running fine last year. No water in engine oil. No oil in radiator coolant. 129k miles.