When driving my ranger when I let off the gas to stop the idle will stay anywhere from 1500 - 1800 rpm's but once I tap on the gas peddle it will return to 1250 rpms. It also only does it after it has heated up, when I first start it and am driving it does not do it, rpm's will always drop to normal ranges when I let off the gas until the machine warms up to levels the fan kicks on and then most of the time I let off the gas rpm's stay up. Once I tap on the gas peddle they drop back down every time. I lubed the throttle cable but that did not help. Any ideas?