Just swapped out dash boards(cracked/broken) on my 97 Yukon & everything seems to be working but tranny. Vehicle engages in each gear but drops in harder w/more force while sitting stationary w/foot on the brake. Very little fwd movement occurs while depressing gas pedal down in drive even when manually putting in 3rd, 2rd or 1st (seems to have a bit more power, not sure if due to lower gear). Reverse seems to be fine. I kept orig ECM, electronics(except PS module) and wiring harness. Check eng light on, cleared memory & after approx 30 seconds it comes on again. Lent out my scanner & will be getting it back tonight. Swapped fuses to rule out, no change. Anyone have any idea's or suggestions as next steps?