Quote Originally Posted by lionelhutz View Post
If it can't go above 4.6V then try using some diodes in series as the load.
I think vilefly's impedance matching idea has it handled. I tweaked on it a few minutes last night and again this morning. Ran for several minutes this morning without setting a code. Evidently the ignition module has pullup circuitry in it as well so what was needed was the correct balance of pullup + pulldown. I'll try to monitor the ADC tonight with eehack and fine tune.