03silverado1500

I have a 2003 Chevy silverado reg cab long bed 2wd with a 4.8L with 120,xxx thousand on it. The fuel pump went out two weeks ago and got it replaced and I love in western Ohio and we've had some really cold weather here like -10 with wind chill and I drove the truck around yesterday for a while and it started dieing out like choking on itself and I turned it off and back on and it ran fine for a while then died on my way home so I limped it home and it died again in the driveway let it sit for a while and cranked a few times and it started and went to the gas station and it died again I ran codes and it came up with bank 1 and 2 lean and I noticed it was back fireing through the intake and took the intake off and on the manifold side of the throttle plate is black and coated with oil it appears. Any ideas on what the issue could be. Pcv valve possibly?

4GMs

With what you're describing I always hunt for anything that may be associated with the work recently performed. Discounting an outright botched installation job, or defective new FP (it's possible) I'd be looking in order of precedence:
-Incorrectly or missed ground re-connections
-pulled, snapped or otherwise accidentally broke off hoses, wires, components anywhere near where the fuel pump or its related connections were made

Of course the cold just may have coincidentally cracked something causing lean (ex: exhaust manifold(s)), which would give backfires. Maybe a big vacuum leak other than the intake itself. Does search come up with anything that exactly matches your symptoms?

BTW, slimy inside intake is not uncommon. It's good you redid the intake gaskets to eliminate one variable. PCV is a normal maint. item. But, I have never heard it outright making an engine die.

03silverado1500

I appreciate it I'm going to check out the pump connections and all that stuf to see what I find out