92 ford ranger auto wont shift unless throttle lifted

Yes, check the vacuum hose going to the vacuum modulator on the transmission. Make sure it's not cracked or otherwise damaged. If that's ok, the vacuum modulator itself could be bad. You might also be looking at a worn timing chain in the engine. Other symptoms of a worn timing chain are the engine runs hot, retarded (late) ignition timing, and engine lacks power. Personally I wouldn't buy it. Hope that helps! Jim