I have a 1995 Toyota Tercel and for some reason the heater only gets hot sitting still or parked I covered the raditor with cardboard and that helped some but this just started last winter would like to have a nice warm winter this year
I would look for a bad thermostat or a vacuum problem so the vacuum controlled blend door what controls heat may not be functioning.
A bad thermostat may be keeping your engine from warming up and that would not only be uncomfortable, but it also is hard on the engine and mileage. I would not rule out a water worn water pump. In addition it may be a bad radiator hose. A bad radiator hose may look OK on the outside, but be collapsed internally.
Assuming you did not run into any over heating problems during the summer, I would start looking at the thermostat.
Typically, the problem is just the opposite - heat gets cooler when sitting still. One suggestion is the blend door. If you have heat sitting still, fresh/cooler air is not coming into your vehicle, because you’re sitting still. When you are driving, an OPEN blend door could be allowing too much air into your vehicle, causing the heat to get cooler. Another suggestion is a clogged or old heater core.