Sound like a fuel pump. If it was the starter it wouldn't even crank. Another thing possibly is the anti-theft light flashing? If so the truck won't start. How many miles does it have? While it may be old, it may be worth getting, but you may have to have a mechanic look at it and give you an idea of how much you may have to put into at first.
It sounds like it's really been bodged, if he knew what he was doing then he'd have diagnosed the fault and changed the bad part rather than randomly swapping parts. It's quite possible that he's created more faults whilst doing so. Were it an easy fix then he'd have done it himself so that he could ask more money for it, wouldn't he?
Buying non-running vehicles usually only makes sense if you have the skills to repair it yourself, thereby avoiding labour costs
Stay away from this truck- period. This thing is 25 years old and anything could happen to it. It will nickel and dime you to death. That's why the guy is trying to off load it.
I'm looking at a 1990 f150 with the dual tanks and has an 4.9l inline 6. The guy said he replaced the radiator, distributer, water pump, fuel pump, starter, plugs, and injectors. He said last time he drove it he said it wouldn't start. But the motor will turn over. He said the starter quit working but he has a warranty on that and the distributer if those are causing the problem. He wants 1500 for it but I don't want to get it and it ends up being a 500 dollar repair. I read somewhere in a forum someone who had a similar issue and it ended up being the fuel tank selector switch. I want someone's input on what it might be?!?!? Any help is appreciated thanks!!