rodney94

I have a 94' 22re yota pickup, 4wd. about 220000 miles on it, rebuilt at about 197000. I just replaced my head gasket about 2 weeks ago, I have only been able to work on it on the weekends since I am in school and have 3 jobs so it has been sitting outside. But after putting everything back together and refiling up my oil and coolant, it started right up. I drove it around the parking lot and parked it in a new place. It drove fine. However, when I would switch gears, my rpms would spike in neural. I started it again about 3 hours later. The rpms were still high 2000-3000. I retarded my distribution, cleaned my throttle body, throttle cable, iac valve, and turned the throttle screw clockwise. After I did this, the truck started up and the rpms were at about 500 but once I reved it up, still in neutral, the rpms stuck and started to climb to about 2000-3000 rpms again. The engine sounds like it is running a little rough too. The exhaust is white as well, I am hoping is from the cold weather and not warming up. I kill the engine before it hits 3000 rpms because I don't want anything more damaged. Please help, I have no idea what it could be!!