2009 escalade rough idle surges limp mode

My Aunt has a 2009 Escalade she bought used with 21,000 miles. She had no problems and loved it until 12-18-10 when she traveled about 90 miles home for a concert. Comes out and starts home, makes it one block CEL comes on as well as SERVICE STABILITRAC, REDUCED ENGINE POWER, SERVICE TRACTION CONTROL. She called me and I told her not to drive it due to the traction control stuff and the 90 miles it just is not worth blowing it up.

Towed it into the Caddy dealer. They cleaned the throttle body and told her that needed to be done every 15,000 miles on her car; and was not covered under the factory warranty and charged her $108.00

Today, one month later (maybe 1,200 miles max), while she is cleaning the snow off the car it started to idle rough and almost died, then the engine raced when she got all the same lights and it was in limp mode. This time I told her to drive it the Dealership since it was only 2 miles. Car had no power, no acceleration but never stalled. Dealer said they would check the codes and see what is up.

I did some checking around on here before and they talked of a wire in the throttle harness and the Dealer told me they checked that last time, and that the guys on the forums like to talk like are techs.

Just curious if anyone else is having the same problems or dealt with this before???

Also last oil change not at the dealership they told her the oil cooler lines were wet. Dealer said they will only do something if they are dripping.