Fuel problem, Rough running

I'm baffled and frustrated! I have an intermittent fuel problem that my garage cannot diagnose. First, it only seems to be a problem when the gas level drops below 1/4 tank. The SES light comes on and the Sub starts to sputter and loses power. When I fill it up the problem disappears and occasionally only feels like I'm missing a cylinder or two. The mechanic says the #2 cylinder is the one that is missing and the O2 sensors are fine. I changed out the distributor cap, rotor, plugs and wires and the problem persists. Any thoughts??

How old a suburban? You could have 'crap' in the fuel tank. When the level goes below 1/4, the fuel pump could be try to suck in this stuff and when the tank is full, the 'crap' is floating way above the fuel pump intake. I have a 96 yukon with 100000 miles and had the fuel tank cleaned out along with the fuel lines. My main complaint was poor power...they found 'stuff' floating in the tank. After the cleaning, my poor power problem improved.

i had a problem with my "96 sub.when it was first started it ran fine then after a few miles of driving it would lose power but you could still drive it,you couldn't stand on the gas or it would fall on its face.everybody i talked to said it was the catalytic converters stopped up,so i replaced them .wasted $340.the problem turned out being the hose between the fuel pump and the metal line in the tank.when i replaced the fuel pump i reused the gm piece which i later found out wasn't a good idea.i replaced the gm piece with a piece of fuel line and problem solved.

have the mechanic hook a fuel pressure gauge to the fuel system and jump the pump at the relay to see how much fuel pressure you have,if its enough,and to see if it bleeds down real fast after he unhooks the jumper.

My Suburban is a 2000 with the 5.3 V8. I had my mechanic check the fuel pressure and it is fine above 1/4 tank. This leads me to believe that the problem could be crap in the tank. What also baffles me is the code for cylinder #2 to misfire. They don't know what it is either. I am about to set a dealer appointment to see if they know what's going on. Also my fuel gauge is very squirrely, at a topped off tank it registers no fuel and the low fuel indicator lights on the dashboard until I drive about 30 miles and it reverts to showing a full tank of fuel. Sometimes it fluctuates as much as a 1/4 tank low then comes back up. I'm puzzeled.