Ok so my beater (90 Corolla 4AFE Auto) has been acting when it starts to warm up, when I start it, it runs fine until the gauge starts going up and it runs fine when its fully up to temp, however in between it has a stutter at idle and sometimes even stalls out, but will start back up only to shut off when put back in Drive. Only way I can get it going is to start it and give it a lot of throttle for at least 15 seconds then put it in gear and go quick. I have taken off the throttle body already and cleaned that as well as the IAC and have replaced the CTS. I have thought maybe water in the line so I have used HEET and Injector Cleaner also there is a new fuel filter on the car. Could this be an O2 sensor or EGR valve issue? There is no CEL coming on so thats making it 10X harder to diagnose. I am just not sure which sensors are effecting the car during the warm-up stage that would effect the cars AFR to make it stutter or stall out, that I haven’t cleaned or replaced.
me = lost
probably not the egr but to check it, hook up a vaccum line to it, should hold vaccuum, to see if the diaphram is working, also can try blowing , should hear the egr open and close.m In my experience , toyotas dont like throwing codes via flash test might want to go to dealer and have it scanned.