I've been trying to diagnose a nightmare, 94 toyota pickup with a 2.4l. It's has a code 13 that comes and goes, it runs rich, and the pid for the rpm in my scan tool shows 6000 rpm at an idle (real engine rpm is more like 750) and when you open up the throttle it runs rough or dies. I've gone through every circuit on this thing and all wiring from the igniter to the ECU is good, no resistance, no shorts to power or ground. I'm not familiar with older Toyotas, is the pcm supposed to put out 12v on the NE circuit? Seems wrong. The igniter also gets very hot after it's been running for 5-10min. Please help, this thing is kicking my a$$