1996 Chevy Tahoe 5.7 4x4 My SUV does has a rough idle from 700-1000 rpms! It hesitates as I accelerate. I have replaced the following: Spider fuel injection system Fuel Pump Fuel Filter PVC Valve Battery cleaned spark plugs It has new spark plug wires cleaned the throttle body about six months ago I have no idea what the fu#k is wrong...my mechanic has had it one week and he can not figure it out either...can you provide some assistance??? Anthony

There is some items that still can be checked : see below the sensor checks with the dtc codes

• Check the Heated Oxygen Sensor (HO2S).
• Check for silicon contamination from fuel or improperly used sealant. The sensor will have a white powdery coating. The sensor will result in a high but false signal voltage (rich exhaust indication). The Control Module will reduce the amount of fuel delivered to the engine causing a severe driveability problem.
• Refer to DTC P0131 HO2S Circuit Low Voltage Bank 1 Sensor 1 .
• Refer to DTC P0132 HO2S Circuit High Voltage Bank 1 Sensor 1 .
• Refer to DTC P0133 HO2S Slow Response Bank 1 Sensor 1 .
• Refer to DTC P0134 HO2S Insufficient Activity Bank 1 Sensor 1 .
• Refer to DTC P0135 HO2S Heater Circuit Bank 1 Sensor 1 .
• Refer to DTC P0137 HO2S Circuit Low Voltage Bank 1 Sensor 2 .
• Refer to DTC P0138 HO2S Circuit High Voltage Bank1 Sensor 2 .
• Refer to DTC P0140 HO2S Insufficient Activity Bank1 Sensor 2 .
• Refer to DTC P0141 HO2S Heater Circuit Bank1 Sensor 2 .
• Check the Throttle Position (TP) sensor. If a sticking throttle shaft or binding linkage causes a high TP sensor open throttle indication, the Control Module will not control the idle. Monitor the TP sensor voltage. A scan tool and/or voltmeter should read less than 0.85 volts with the throttle closed.
• Check the Engine Coolant Temperature (ECT) sensor using the scan tool to compare the engine coolant temperature with the ambient air temperature on a cold engine. If the coolant temperature reading is more than 5 degrees greater than or less than the ambient air temperature on a cold engine, check for a high resistance in the coolant sensor circuit or the sensor itself. Refer to DTC P1115 ECT Sensor CKT Intermittent High Voltage Diagnostic Aids or DTC P0118 ECT Sensor Circuit High Voltage Diagnostic Aids .
• Check the Manifold Absolute Pressure (MAP) sensor response and accuracy. Refer to DTC P0106 MAP System Performance

• Check for vacuum leaks. Vacuum leaks can cause a higher than normal idle and low Idle Air Control ( IAC) counts.

Ask your mechanic to check the egr valve. If the valve is one of those three solenoid ones then it could be acting up and not set a trouble code. He may need to pull it off to see if there is a piece of carbon stuck in it.