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got 1990 corvette and engine code 22 and 42 idels great but when get on the gas it spits and sputters he;p would be great
one is throttle position sensor, tps. other is electronic spark control, est.
disconnect tps to see if it helps. check the EST connector near the battery, tan wire in a "cocoon" coming from ecm to distrib. it is likely disconected, code 42.
The code 42 could be historic. The ECM will set this code when you disconnect the EST connector to set the timing. The ECM will remember the error code forever if there is a current error. There are two ways to clear historic error codes:
1) Start the car 50 times with no current error codes.
2) Disconnect the power to the ECM. The easiest way to do this is to open the ECM power connector attached to the positive battery terminal: