1994 Chevrolet S Series

MY TRUCK FOR SEVERAL YEARS NOW HAS HAD AN IDLE LOPE AND MISS WHICH I HAVE BEEN UNABLE TO CORRECT. I HAVE CHANGED THE SPARK PLUGS AND SPARK PLUG WIRES SEVERAL TIMES. I HAVE REPLACED THE THROTTLE POSITION SENSOR AND THE MANIFOLD ABSOLUTE PRESSURE SENSOR. ALSO ,REPLACED THE FUEL INJECTOR, FUEL PRESSURE REGULATOR, AND ALL ASSOCIATED HARDWARE THAT IS TO BE REPLACED AS A UNIT ON THAT MODEL OF VEHICLE. THE EGR SYSTEM HAS BEEN REPLACED UNDER RECALL. UP TO THIS POINT THERE HAVE BEEN NO SERIOUS STARTING PROBLEMS. THE ONLY INDICATION OF A PROBLEM HAS BEEN THAT THE ENGINE CHECK INDICATOR WOULD BRIEFLY LIGHT UP UNDER SUDDEN DECELERATION. THE ENGINE CHECK ENGINE" LIGHT HAS NEVER BEEN LIT TO MY KNOWLEDGE, NOR HAVE I BEEN ABLE TO RECOVER A CPU FAULT CODE USING PUBLISHED PROCEDURES. THAT IS PART OF WHAT HAS BEEN SO MADDENING ABOUT THIS PROBLEM--VEHICLE DIAGNOSTICS ARE NOT DETECTING A PROBLEM, SO I BECAME FRUSTRATED WITH REPLACING PARTS THAT WERE NOT DEFECTIVE. I HAVE HAD THIS TRUCK TO 3 GM AUTHORIZED DEALERS: PRATER CHEVROLET IN LAFOLLETTE TN, FOX CHEVROLET IN CLINTON TN, AND REEDER CHEVROLET IN KNOXVILLE TN. THAT HAS BEEN ANOTHER FRUSTRATING ASPECT TO THE PROBLEM. SINCE THE DEALER SERVICE DEPARTMENTS HAVE BEEN UNABLE TO RESOLVE THE PROBLEM, I HAVE BEEN STUCK WITH TRYING TO FIND A RESOLUTION ON MY OWN. ONLY NOW THE PROBLEM IS GETTING WORSE. UNTIL RECENTLY THERE WAS NO NOTICEABLE MISS IN THE DRIVING SPEED RANGE OF THE ENGINE. NOW THERE IS AND IT WILL ONLY GET WORSE, I'M SURE. WHEN THE TRUCK IS IDLING IN PARK, THERE IS ALSO A NOTICEABLE MISS AND VARIATION OF ENGINE SPEED ON THE TACHOMETER, FROM IDLE ALL THE WAY TO 3500 OR 4000 RPM. I HAVE NOT ACCELERATED AND HELD THE ENGINE TO NEAR REDLINE SPEED IN A NO LOAD CONDITION. I AM NOW TO THE POINT WHERE I AM CONCERNED ABOUT THE SAFETY OF THIS VEHICLE IF IT SHOULD STALL WHILE IT IS BEING DRIVEN IN HEAVY TRAFFIC AND/OR INCLEMENT WEATHER. *AK

I OWN A 1994 CHEVROLET S-10 WITH A 4.3L V-6 ENGINE WHICH I PURCHASED NEW.. IT CURRENTLY HAS APPROXIMATELY 88,000 MILES ON THE ODOMETER. FOR SEVERAL YEARS NOW THIS TRUCK HAD AN IDLE LOPE AND MISS WHICH I HAVE BEEN UNABLE TO CORRECT. I HAVE CHANGED THE SPARK PLUGS AND WIRES SEVERAL TIMES. I HAVE REPLACED THE THROTTLE POSITION SENSOR, MANIFOLD ABSOLUTE PRESSURE SENSORS, FUEL INJECTOR, FUEL REGULATOR, AND ALL ASSOCIATED HARDWARE THAT SHOULD BE REPLACED AS A UNIT ON THAT MODEL AND FUEL SYSTEM. THE EGR SYSTEM HAS BEEN SERVICED UNDER RECALL. UP TO THIS POINT THERE HAVE BEEN NO SERIOUS DRIVEABILITY PROBLEMS. THE ONLY INDICATION OF A PROBLEM HAS BEEN THAT THE "CHECK GUAGES" INDICATOR WOULD BRIEFLY LIGHT UP UNDER SUDDEN DECELERATION. THE "CHECK ENGINE" LIGHT HAS NEVER LIT TO MY KNOWLEDGE, NOR HAVE I BEEN ABLE TO RECOVER A CPU FAULT CODE USING PUBLISHED PROCEDURES. THAT IS PART OF WHAT HAS BEEN SO MADDENING ABOUT THIS PROBLEM--VEHICLE DIAGNOSTICS ARE NOT DETECTING A PROBLEM, SO I BASICALLY BECAME FRUSTRATED WITH REPLACING PARTS THAT WERE NOT DEFECTIVE. I HAVE HAD THIS TRUCK TO 3 AUTHORIZED GM DEALERS: PRATER CHEVROLET IN LAFOLLETTE TN, FOX CHEVROLET IN CLINTON TN, AND REEDER CHEVROLET IN KNOXVILLE TN. THAT HAS BEEN ANOTHER FRUSTRATING ASPECT TO THE PROBLEM. SINCE THE DEALER SERVICE DEPARTMENTS HAVE BEEN UNABLE TO RESOLVE THE PROBLEM I HAVE BEEN STUCK WITH TRYING TO FIND A RESOLUTION ON MY OWN. ONLY NOW, THE PROBLEM IS GETTING WORSE. UNTIL RECENTLY, THERE WAS NO NOTICEABLE MISS IN THE DRIVING SPEED RANGE OF THE ENGINE. NOW THERE IS AND IT WILL ONLY GET WORSE, I'M SURE. WHEN THE TRUCK IS IN PARK, THERE IS ALSO A NOTICEABLE VARIATION OF ENGINE SPEED ON THE TACHOMETER, FROM IDLE ALL THE WAY TO ABOUT 3500 OR 4000 RPM--I HAVE NOT ACCELERATED AND HELD THE ENGINE TO NEAR RED LINE SPEED IN A NO LOAD CONDITION. I AM NOW TO THE POINT WHERE I AM CONCERNED ABOUT THE SAFETY OF THIS VEHICLE IF IT WE*AKRE TO STOP, IN SAY, HEAVY TRAFFIC AT INTERSTATE SPEED.