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Q: won't stay running on 1991 Chevrolet S10

It keeps giving the same 3 codes. map,vss,tps and i replaced all 3. still doesn't what to run.
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MAP and TPS sensors share the same 5 volt reference signal from the computer (ECM) , have you checked for voltage at these sensors with the key on engine off sensor connection disconnected from the sensor 5 volt should be present at one wire at each sensor or you must trace the wire back to the computer and see if it is a wiring problem , computer problem or power/ ground issue.
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I checked the wires and the voltage and all good, but when i take the tps off the tpi and hold it to full throttle and hold the vacuum line going to the map sensor it runs good. Im think it mit be the ecm or.. If you have more info.. thank you.
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