My 2005 ram 1500 slt 5.7L Hemi is stalling when shifting from reverse to drive. It also is throwing code p0158 after stalling. Have tried dry gas and injector cleaner. When it doesn't stall the idle drop down to 500rpms then goes back to 650. Any ideas? Thanks in advance.

 

Code is for post cat O2 sensor, dry gas or injector cleaner ain't gonna do nothing for that. Normally I'd say the sensor is toast and to replace it, but a sensor (especially a downstream one) wouldn't make it stall.
Your cat may be clogged or you may have an exhaust leak which could cause a stall. First thing I'd do (because it's the easiest) is check for an exhaust leak, especially around the exhaust manifold. Manifold bolts are known to shear on the 4.7 and 5.7s pretty regularly.
If you can't detect a leak, then I'd probably do the O2 sensor, since it's a lot cheaper than a cat and with an '05 it's about due anyway. If they strike out, I'd point to the cat.

Oh, and it could be a badly clogged throttle body - when's the last time you cleaned it? Has it been more than the recommended 30k miles???

 

Cleaned the throttle body. Checked the PCV. Truck only stalls when shifting from reverse to drive with the wheel turned. No check engine light though. Also happens more often when on a incline and turning right into a parking place???