Infiniti G20 Sputters and dies

When the weather is cold (ie Georgia cold around 40F) and my car is in Drive but my foot is on the break my car will shudder and then die.

I can avoid the dying if I take the load of the engine by putting my car in Nuetral /Park or if I can take my foot of the brake and start driving.

When the shuddering is happening my headlamps dim and the RPMs indicator bounce from 1000 to 2000 RPMs, the needle bouncing and dimming are synchronized.

The car will start up again immediately after it stalls.

I took it to the mechanic he said he couldn’t find anything but he tuned my idle to see if it would help… it hasn’t.

What year and mileage?

“tuned my idle…”??
I’m going to suggest you have faulty IAC valve (Idle Air Control) and/or a dirty throttle body for which you can buy and spray into the throttle body after removing the air intake hose.

sorry it’s a 1996 with 120K