94 Ford Bronco 5.8 E4OD 214 k

runs eratic in gear 1-2-3 fine in OD when OD cancel depressed also rough, at these rough periods ck eng flases rapidly but when code reader eng off test fuel pump relay kicks in wipes out communication to ECM preventing code, 1st cold start in morn ck eng on but warms D and R eng runs well as if possible issue with low speeds– i am perplexed