Weird idle issue on decel
 

Hello all, after numerous times searching many forums for a specific answer and trying many different fixes, I am at a loss. During normal driving once the car is fully warmed up, it will sometimes die out on decel. This is not all the time yet most times the idle will droop.
I have tried cleaning the throttle body iscv and even replaced the coolant temp sensor on the back of the head. My car is a 1990 miata with a fm2 turbo kit and ms pnp2. I tested for boost leaks and vacuum leaks with no signs of any. I wonder if I am missing something super simple. I appreciate the help!
Joe

Are you using closed loop idle? What is your dashpot adder %? What is PID delay set to?

I'll have to hook the laptop up and take a deeper look. Thanks for giving me a starting point.

I have the same issue on my stock ecu, stock engine.
Whenever the engine's cold and I come to a stop, you can feel the car wanting to stall. RPMs drop to low 400's and pick right back up. It's alarming at times especially in traffic haha.

problem solved. The AFR's for idle were way too rich causing the car to stutter, also I upped the mapping for higher coolant temp. which seems to have solved any off throttle decel issues.