two things to look at as I have fixed hundreds of those things. Get an analog voltmeter and do a voltage sweep with key on, engine off on your TPS (throttle position sensor). Looking for a clean sweep from around .5 volts to just over 4.5v WOT. Those things,, although fed through a 5v reference, will notoriously get carbon tracking on the grid giving an open in signal return yet no CEL. And data is too slow to catch it.