so i moved to a new 4 in 1 esc...i need a little help locating the problem.. coz google gives only right results if correct questions are asked
i decided to cheap out ( kind of) and buy a racerstar 4 in 1 esc
this one    -- i flashed it to the latest blheli firmware and calibrated all the esc in the suite
https://www.banggood.com/Anniversary-Special-Edition-Racerstar-REV35-35A-BLheli_S-3-6S-4-In-1-ESC-Built-in-Current-Sensor-p-1180734.html?gmcCountry=IN&currency=INR&createTmp=1&cur_warehouse=CN&utm_source=googleshopping&utm_medium=cpc_ods&utm_content=heath&utm_campaign=pla-ods-in&gclid=EAIaIQobChMIlpuWzNH72wIVTIaPCh3hfgYJEAQYASABEgITvPD_BwE

reviews say its good ( but then i rarely see bad reviews on b.g) .

here is my prob ( note i did not face this problem with the spedix 30A individual esc so my motor and f.c are good --only the esc has changed)

ON  a 4S when i punched the throttle the quad shoots up but i can hear a vibration/ stuttering/ refusal of motor to spin at full power...
i tried it a couple of times and then  at 50 metres height at one point my quad totally died and fell down like a rock( no damages) ..and flew again normally!!

i thought it has to do with calibration or timing issues of motor/esc...so i took the props off and punched the throttle..no problems ..everything was smooth. the problem does not exist when using a 3s battery
so it has to do with esc incapable of handling power???
how do i confirm what the problem is.. what do i look up on google??( tried most stuff but no use)
note ( my motors are 2500kv- tmotor and are running heavy props 5050c)
cant fly a quad peacefully knowing it can fall out of the sky anytime ...! any help much appreciated.

Look up motor sync issues

https://www.propwashed.com/fixing-a-stutter-on-your-brushless-motor/

@ambattuhari
The first 3 para of the article were as if written for my quad today.
.... I was doing exactly that...punching and reducing and punching throttle rapidly ...
Looks like twas a desync / motor timing issue.. will change it and try.
Thanks for the tip guys.

Hi, also add a low ESR capacitor , (even though the manufacturer says no need) because damped light is always on in blheli S

Will definitely do it . First this tomorrow. 👍

Prob solved , I did these things all together so I don't know which one has solved it.
Changed idle throttle from 4% to 10%
Changed motor timing from medium to medium-high
Added a cap.
Flies great. Shoots up like a rocket in a sec ...at max power..no stutter etc.
:-)

Hi,
  Glad to hear that. Happy flying .

PS. You must be aware of the beacon facility in blheli. But beware, it heats up the motors !

That's a great option , but i am using rssi values to locate if lost.
Yesterday I asked a friend to hide it in a field..I then found it using rssi ...
I might change the startup music in blheli. XD