I’m the original owner of an 1989 GMC K1500 4x4 truck. I have had very little problems with this truck over the years even though it has over 267,000 miles on it. However, since it is so old, I have not fixed the A/C, driver’s side window operaton, or exhaust. I have now begun having problems with the fuel system and believe I need a new fuel pump or new wiring for the fuel pump. it is hard to start and has died twice on the road. I can restart it with starter fluid. Either way, it will involve removing the gas tank which will cost several hundred dollars. The four wheel drive works fine, but the body is rusty. Is it worth spending the several hundred dollars to fix the fuel system or should I junk/sell it? I do have another vehicle, but it’s nice to use this truck in the winter and to save on my other vehicle.
Since you have basically neglected the vehicle in the last few years, I would sell I “as is” and get something newer. That year Chevy/GMC trucks were not sterling examples of quality and reliability.
There will be many more things to fix soon at that age and mileage.