RPM drops when coming to a stop
 

hello guys. just want to ask, my BRZ rpm drops when AC compressor turns on while coming to a stop making the car shake. I think it drops around 580 to 550rpm. It doesn't do that if the car is on stand still. It doesn't always happen, but getting a bit irritated. haha. Is this normal? thanks again :)

normal

yup. normal. give a gas little in neutral if you hate it

it shouldn't, actually. The ECU should compensate for idle going below and above certain rpm. AC turning on, etc will make the idle lower, but the PCM should raise it. Usually with timing adjustments, or throttle adjustments. Back in the day, they used idle air control devices, but I don't think that ours has one of those being that it has drive by wire electronic throttle.

Id say to clean the throttle body really well, and check for air leaks/rips in the intake pipe.

I'd also look at my fuel trims at idle. If its overly lean or overly rich, that would be a clue

But it will dip for a second before the ecu can create a compensation

stock tune tends to do like that, a retune would fix it (unless the tuner keep idle settings as stock as many do lol)