Had the same issue with limp mode coming on when driving after about 5 mins and the engine heated up. Removed EGR as per above instructions and cleaned. A toothbrush made this easier too to get the big chunks out for starters. Then clean/degrease with your weapon of choice and put it back together.. After that I noticed a vacuum hose was a little loose as well. Stuck a new clip on and tightened. After the the engine light disappeared and no more issues.