94 SLS V6 262ci 4.3L Sonoma. Replaced battery, all connections are tight so Sears said. Still acting like not getting gas. Filled tank up and went to start truck and it almost didn't start. Drove out on highway and when pushing pedel started to bog down. While at a stop, wants to stall. Now parked, turned off and won't start. What do you think?

Turn key off and on 3times w out startn. On4th try startn it. If goes then fuel pump etc is bad. May also hav ignition problem like bad dist cap or wires. Getta repair manual

Lots of black smoke in the back i had a few problem like that it was the spider in the intake there a central injection system in it its 6 plastic pipe that goes to the cylinder 1 per cylinder 1 or 2 pipe crack and spray gas in the intake your oil must smeel like gas even if its not old let me no after that your car gonna run like new its not a cheap part but you got no choise thats for the question james

Hard to say. The gas cap might have been loose. That will turn the Chk Eng light on. When you filled the gas tank you made the cap tight again.

Get the codes read again if the light comes on again.

check your battery posts and terminals are clean, if is ok, you can check the wiring the charing circuit, maybe the guy installing the stereo broke a corroded wire off.
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It's the vent valve, and it's connected to the charcoal canister near the rear axle. Might be on top of the tank.

Try changing the fuel lines, if they are cloged from debris that could be the cause.

U have lost the battery, check the cables, if they are clean (no corrsion) replace the battery, modern sealed batteries fail like this, crank fine and then puff nothing, happened to at least 5 times over the years and saw it all the time at work.

Evaporator vent silenoid at rear by gas tank is most likely stopped up. Is the check engine light on? If so, take to Auto Zone and get them to scan it for free. Get codes only and post them.