Hey everybody I got a garage to switch the injection pump in my 93 Sierra because it wasn’t starting after the engine was warmed up… they were able to swap the injection pump, but it will not shift into overdrive now. The Tcs has been adjusted and swapped out. I’m new to the code reading on these trucks… but I think it’s telling me 12, 21 and 85. The garage that returned it to me figures there must be a faulty wire somewhere. I’m gonna check all the grounds for now . My next step will be to take it to gmc dealership:/ anyone ran into this issue?