Engine Performance problem
2000 Chevy Astro 6 cyl Two Wheel Drive Automatic 122000 miles
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Both independent and dealer mechanics have work on this problem; replacing air and fuel filters,checked and repaired all loose or damaged wiring/connectors. Checked fuel pump and pressure okay.Checked distributor cap,wiring harness, spark plugs and coil okay. Cleaned EGR ports and replaced valve. At dealers suggestion, replaced catalytic converter which turned out to be okay.Tested the IAT,MAF and the MAP and all are in order. Onboard Readiness reports: All monitors and sensors okay. PASSED. But engine after reaching normal operating temp. Starts to hesitate durning acceleration which throws the trans out wack;down shifting and up shifting till the engine becomes stable. This is an intermitne problem and acts normally after a dozen miles or so. Any ideas?