I bought a 2011 f 150 with the 3.5L ECOBOOST with 75,000 miles 2 months ago. It has the shudder under moderate to hard acceleration with the blinking engine light. I drilled the 1/16th inch hole like everyone says to do, had a little water come out, and it has not done anything to fix the problem.

 

I'd change the spark plugs. If they are original they are way past due, should be done every 40k.