2000 Z24 has random misfire, EVAP code, and TRAC OFF light comes on intermittently leading to hard shifting.
Vehicle is searching for idle, idles high in Park, barely idles in drive/reverse/neutral. Fuel pump and fuel filter replaced.
Misfire is random, per OBD2 scan, and constant throughout the RPM range, though most noticeable at lower RPMs. Car dies coming to a stop.
I believe the misfire and the EVAP code to be related to a vacuum leak, however the shop that replaced the fuel pump and the fuel filter reported no vacuum leak throughout the system (though I can hardly believe that with what I've been reading about the two codes being related).
Checked FPR vacuum line for any breaks, fuel pressure is good.
Would such a massive leak from the EVAP system cause a misfire that badly without a decrease in gas mileage?
When the TRAC OFF light is on, the transmission shifts hard, however, when the light is off, the transmission shifts fine. All sensors seem to be plugged in (the two on the shift lever solenoid(?), and the one at the front of the transmission). Trans has enough fluid in it and it's clean from what we can tell.