idling issues
 

Alright so about 2 weeks ago my car started to have trouble idling. It would jump up and drop down after it warmed up but never had any trouble while driving. It threw a p0300 and 2 downstream oxygen sensor codes for the same sensor. I found that the upper intake manifold had a vacuum leak and a wire for the sensor was cut from dragging on the ground. Fixed the wire, replaced the manifold gasket and cleaned the throttle bodies and maf sensors. Cleared the codes and took it for a drive. Idled fine but stalled while approaching red lights three times. I thought maybe the ecu needed to relearn and did an ecu reset. Now the car will idle fine 95% of the time and then occasionally stutter like it will die and then catches itself but has not stalled for about 50 miles now, currently still waiting to see if the check engine light comes back.

Sorry about the long post, my question is if anyone has any other ideas about what could be causing the occasional stumble, I've read plenty of people's cars stumble like this, but I don't want to call it normal since I've had an idling issue so recently

First thing I'd look at is the repairs to the sensor wiring. If you have high resistance, it can cause problems.

I won't have access to my multimeter until Monday but I'll look into that then. I should clarify I didn't repair the wire until after the car stalled on my test drive.

I forgot to update but incase anyone stumbles across this with a similar issue my solution was to recalibrate the throttle bodies. I wasn't aware the throttle bodies had a relearn procedure to do after they are removed for cleaning. But sure enough after I did the procedure the car no longer stumbles and stalls.

Thanks for the update.