Engine surges when cold

It has gone progressively worse, when the engine is cold ie 20 degrees fahinheit to 40 degrees fahinheit, the motor surges to 3000rpm and back to 500rpm, very quickly till the motor warms up, and now has no power going up hills, it has gotten to the point when its cold it just nows rough idles and stalls, and will not rev up, its donebeing drivable{towed home}either its egr valve or throttle position sensor and o2sensor? Please help me could it also be coolant temp sensor thank you for your help thanks bob hines