I posted this on the LS1 Tech site but never really got an answer so thought I would give a shot to the experts here. I have a GMPP LS3 crate motor with the GMPP E67 controller and harness installed in a 69 Camaro with a T56 transmission. I keep getting an intermittent P0507 Idle Speed High code and CEL along with an intermittent de-activation of the reverse inhibit. Could not figure out what was going on so started continually monitored with HPTuners and there seems to be a relationship between losing the speedo in the ECM, losing the reverse inhibit, and then the CEL for the high idle. What is strange is that my electronic Autometer Speedo and tach still work great. I have rechecked the wiring and confirmed I have the VSS connected to connector C3 pins 66 and 67 and the Speedo is connected through the bulkhead connector pin D as per the instructions. I do not understand how this works because I thought the controller passed the signal on to be used by the speedo. How can the ECM lose the signal but the speedo still work? Would really appreciate some help on this. Thanks
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