are h and d series spark plugs different?

 

I dont know if they are the same or not, but I had a d15y7 that I had just bought a set of plugs for a few weeks before I swapped an h22 into my hatch. I figured the plugs were new so I put them in the h22 and didn't have any problems...

 

thanks for the info. cuz i bought some ngk plugs and autozone delivered the g-po wer platinum plugs. my cousin has a d15b and he got the v-powers and we traded but my car will start and run but if i go out and get on it when i let it idle down it will die and ididnt know if it was the plugs or not.