Engine choking and stalling after hard acceleration

NeoSHNIK

Thanks all! Today I bought OEM air filters and installed them. I cleaned TB, although somehow after 55k miles it was still pretty clean. I also looked at the intake tubes and didn't see any oil in them from the K&N.

I put it all back, reset the ECU and drove the Z like it was stolen for 15 miles. Car accelerated really well.
I will monitor what happens. May be the K&N filter was the red herring and I just had bad gas... or may be my fuel injectors are failing. I might put that Chevron Techron into the fuel tank next time I fuel up...