I’ve been working on a 1993 Eldorado with 62k miles that I was gave and have done a lot of stuff to but have an interesting issue when driving it. For the background I’ve done the following: all new brakes and fluid, new intake cover gasket, map sensor, new OEM Idle Speed Control Motor, cleaned the throttle body and put on new gasket, air filter, coil packs, fuel filter, fuel pump (sending unit was not working), and new fuel. The idling is perfect at in park but when I drive it down the road it’s erratic up and down and when I put it in neutral it continues to go up and down for a few seconds and returns back to normal and I can put it in gear and it will eventually do it again in a few minutes. I feel like it’s still related to the ISC needing to learn, but the behavior while driving makes no sense. Any thoughts or suggestions? Anything would be greatly appreciated.