2009 Toyota Corolla with engine idle fluctuating surges with foot on brake

[MG]

09 corolla. 102k when engine is fully warmed up. When stoped with your foot on the brake the idle will surge between 650 and about 450 rpm. Will only do this while foot is on brake pedal. Leave it in gear and set parking brake idle is fine. I’ve tried cleaning throttle body and throttle reset. Have throttle body swapped right now. I capped off the vacuum port to the brake booster. Same problem continues. Anyone seen this before?

With those corollas make sure the 2 ground bolts are clean under the battery. Take the bolts outs and clean the threads. Fixed

 

[TonyL]

Where you able to figure this problem out? I'm having this exact same issue with my 09 corolla, 125k miles. It feels like my engine is pulsating when foot is on brake. Only happens when I'm idle at a stoplight.

Problem occurred after I've had my engine coils replaced after having them fail on me in the middle of the road. Heads up, I'm extremely ignorant when it comes to automotive repair. But, I did my research and cleaned up the throttle body, and checked the MAF for any visible debris/gunk. Still this problem persists. I've even disconnected the battery and plugged it back in after a while (to have the computer reset) and it still persists. It's been about 6 months now since I've noticed this weird behavior from my corolla.