Purchased a 1986 D150 from Facebook marketplace in town in Jan '22 with 72k miles on it, cap on the bed, and minimal rust to the body or frame. The problem is the truck only started with a jump pack and did not run/drive. I replaced the battery and alternator before determining it was a bad voltage meter, and once that was replaced it was at least starting, running, and driving. New wheels and tires and replaced the entire brake system (front pads and rotors, rear drums, all brake lines) as well as having to replace a radiator that began leaking out of nowhere last year and replacing the power steering hoses. When I had it in for the radiator they did an oil change and the odometer suddenly stopped turning. Is there any way to fix that? If I ever go to sell the vehicle I would like to be as transparent as possible so would like to get that rolling again on a truck with such low mileage. The only other problem I am currently experiencing may be a misfire? Going to try and diagnose that soon, but the truck when at a dead stop or after coming to a stop will sometimes lurch forwards while braking, or when accelerating from a stop will lurch and/or stall and it seems to struggle going uphill sometimes. Thinking it could be either a misfire or an issue with the transmission. Any advice would be appreciated!

Also, what is the largest tire size I can put on without having to lift the truck or have the tires rub? I was thinking 29 or possibly 30. Will upload photos of the truck to the thread later.

 

It's probably a broken gear in the speedo..... not sure you can get individual parts for those, would probably require replacing the whole thing..... (maybe the entire cluster... not sure on that year.)

 

Hook a vacuum gauge into the vacuum lines to see what the engine is pulling. Struggling might be something simple like a moue nest in the exhaust or a muffler that has rusted inside and collapsed. You should pull 17-20 inches of vacuum at idle. If you're pulling something like 12 inches, you have a partly plugged exhaust.