gm code p1518-----Need help fast!

[yellowGT]

Here's is the situation.....We have a 2001 suburban 1500 with the 5.3 if that matters. We can turn the truck on and drive for a while and then it just shuts off. After waiting a while I can get it started but only with " reduced engine power" on the display screen on the dash. After waiting a while longer we can then turn it on and runs normal. I Researched the code and im getting that its the throttle actuator control module. How do I fix this or has anyone ran into this problem before. Need help pretty quick since its wifes truck and uses truck to bus our kids around. Thanks.