engine pinging
 

When accelerating in second gear at a relatively low rpm (around 2800) there is a bit of engine pinging. I use Sunoco 94 gas, and I could understand this with cheap gas...
Of course these cars are meant to be driven and accelerated at higher rpms, and generally I'll double clutch and raise the rpms to down shift etc.
The fact is sometimes I slow down almost to a stop without downshifting into first, hence the rpms are low in second gear.
Anyone get this pinging or know why?