This is just an idea but it's worth a try. I think the P0170 code is a fuel issue. My first thought, based on my 91 accord, is the coolant temperature sensor. If it is failing then it reports incorrect data to the computer, the computer that controls your fuel and ignition timing. The computer doesn't know it's bad information, it just responds and makes adjustments. My 91 had some issues similar to what you are reporting and the sensor was the fix. If I remember correctly, the part was less than 20 bucks. It could even be corrosion on the connector for the sensor, after all, the little rubber boot that protects it is 15 years old.

Worth a try

Dan