[rhandwor]

With your mileage and having to move the timing is a sure sign of a loose timing chain. I think it is stretched about 60 degrees and the computer keeps hunting finds a good spot then the timing changes moving the rpm up and down.
A new two piece timing set and gasket & seal with a readi sleeve is what the engine needs. 200,000 on the original set it is way past time. The parts will be cheaper than a tow home. Rent a propane heater for the garage and find a good warm day. You should be able to do this in one day.