id_escalade

Hello I have a 2005 Chevy Uplander that started having issue 6-8 months ago. When it first started having issues it would stumble and die in reverse but would drive fine in forward. One day it died and would crank but not start. I tried to start it again after a few ours and it started and ran good but had a code for crankshaft position sensor. I replaced the crankshaft position sensor and it had been working great until a few weeks ago. It had similar issue would start after it sat for 30 minute would start right up. I replaced the crankshaft position sensor thinking it was defective or went bad again but the new one had the same results. So I cleaned the throttle body and it was running better but when I put it in reverse it will back up without stumbling until I press the throttle the it stumbles and almost dies. I thought it could be the throttle body as this is a similar symptom as idle are control valve. I bought a throttle body from the junkyard to see if it improved and it was worse. Now I have a PO120 with reduced power warning and the throttle works in park but if I put it in gear the throttle doesn’t work. I tried the GM throttle body relearn and it didn’t change. I put the old throttle body back on and the reduce power warning goes away but still has same issue. At this point I’m not sure if the newer throttle body is bad or just not paired or if there is another issue. Has anyone had similar issue and able to resolve it?