I'm running out of ideas and money throwing parts at this problem. My 1987 4runner has 137k miles and has been pretty good to me until it recently developed a miss under load. This miss is inconsistent meaning that sometimes when I accelerate it's fine and sometimes it hesitates bad. I've installed the normal tuneup parts, O2 sensor, tested both AFM and TPS, installed a LCE fuel pressure gauge (~ 40psi), installed a new ignition coil, PCV and cleaned the throttle body. When testing the AFM the resistance did not go up in a completely linear fashion but never shorted out and never went to an open circuit which is what the instructions I was using warned of. All plugs are reddish brown and seem to have a healthy spark. At this point I'd think injectors maybe? I ohmed the #1 injector since it is the only one I can reach with the plenum on and it was within spec. How can I figure out which cylinder is missfiring since it's under load? Pulling each spark plug at idle makes the engine run rough.