88 S10 Bllazer 4.3 TBI stumbles & dies

HELP...! :uhoh: My blazer starts fine after a couple of cranks, runs okay until the idle change. Then it surges until it finally dies. If you try to rev it, same thing. I know it has to be ignition or fuel. Checked plugs & wires all fine, changed the distributor cap not so long ago. Changed the fuel filter, but haven't cheked the fuel pressure yet. Had no diagnostic codes when I checked. I think it's the fuel pump or regulator, any suggestions?

Check the gasket under the throttle body. They have a bad habit of sucking in and causing a vacuum leak.