My non-turbo 744 loses power after it is up to temperature and when the overdrive (ZF Auto-Trans) is in. Until it is up to temperature, it has power as it did when it was younger. I replaced the mass-meter with a used one, which helped some, but the problem remains. The problem occurred around the time I put a metal radiator in it and new anti-freeze. I probably should have changed the thermostat because the engine heat gets to the red mark before the thermostat opens whenever I change the anti-freeze (I also drained the block). I suspect it has an aftermarket thermostat without the little bypass hole. Anyway, the engine didn't seem to be hurt since it doesn't use more oil and the power is good when the engine is cold. I guess there is a temp. sensor which feeds the computer. I'm wondering if it went bad when the temp. got to the red. It has 218,000 miles on it. Thanks.