I have a 2003 1500 Avalanche 5.3L 38,000 miles on it. It stalls mainly during deceleration and left hand turns. No shaking or stumbling it just stalls. It will start right back up and run fine. there are no codes coming up on the scanner, check engine light is off, and fuel pressure test is normal. any ideas?
“Stalls during deceleration and LEFT HAND TURNS.” Might be electrical. Check the battery hold downs. Disconnect the battery cables and clean them, and the battery terminals, with a round wire brush. Loosen, and re-tighten, the battery cables where they attach to the truck body, or engine, or junction.
Does it have 1/4 to 1/2 tank of fuel in it?
Seriously… if it only dies when you are decelerating making a left hand turn, what is a fuel pressure test going to tell you if it’s done standing still on level ground?
Try the fuel pressure test again with the gauge mounted so you can see it and read it clearly through the windshield while sitting in the passenger seat, and see if there is a sudden loss of fuel pressure while a helper drives under the dynamic conditions that provoke stalling.
Also make sure all sensor and wiring harness connectors are fully seated.