98 4runner, v6.

So a while back my engine light came on and I took it into my mechanic. It gave the code p0505 for the idle control valve. So he cleaned up the valve door, (i guess), and cleaned the sensor and reset it. A few days later It came on again so i took it back into the shop and the took the idle control unit apart and cleaned the inside. He did find what looked like a single piece of dog food in there. covered in carbon. reset it again. The next day the light came on again. It seems to do it in the morning but if the truck warms up it doesn't come on. If i drive it enough to warm it up and let it sit parked for a few hours the light won;t come back on when i start it. It idles at about 1400 cold and 850 warm. (if the light is on). if not, 700 warm not sure what the cold is. I did have him replace my timing belt and water pump about 3 weeks before it started. not sure if that can be related though. If anyone has any good ideas i would appreciate them.

thanks
mike