sometimes my idiot light flashes too....ive read the codes and mine flashes due to the cat. convertor being gone, and letting an over sufficent egr flow....just an idea....
btw...my egr valve/transducer kajigger is all new, as with the vacuume lines and what not running to them, i also swapped my little solenoild switch things on the front of the engine when i got my new motor.....when i got the engine, i re-ringed and put new bearings into it, and cleaned every little passage/port on the intake manifold, so i know mine isnt an issue with the egr system itself...ive had a couple other vehicles that had this same exact issue after my exhaust work....which on all 3 of my vehicles i have ive enlarged the exhaust size, and put the smallest case sized turbo muffler to somewhat tame the noise....and removed the cat. so i believe that is my issue