Truck is now stumbling at idle what should I be looking for?
So it was finally time for me to upgrade from the old SCPI spider injector to the new MPFI and get some other work done. So on the weekend I cut out my catalytic converts and installed some new aftermarket ones and new O2 sensors, changed the oil and threw in some fresh ACDelco plugs. Then I tore into the engine and unhooked the million electrical connectors, pulled off the cover and swapped in the new MPFI injector from NAPA.
So day one everything seemed to be running better. Except I was still getting an OBDII error code that Bank 2 Sensor 1 wasn’t preheating. I swapped the two front O2 sensors from side-to-side and haven’t seen the error since. BUT around day three the engine now doesn’t want to start until I have cranked it for 10-15 seconds and runs really rough at idle. In the truck it feels horrible but when I pop the hood it’s hardly noticeable. Under acceleration it seems to be fine. Also it smells like it may be idling rich but I’m not sure how to confirm that.
What should I be looking for? At this point in the repairs I’d hate to bring it into a shop but that might be my only hope.