Instruct: Classify Amazon reviews into positive or negative sentiment
Query: POOR QUALITY!

I had them put in my Buick after reading reviews on Amazon that the MPG was great. My old plugs were extremely bad, some with no electrode. I'm not getting great MPG, only average, but of course better than the worn out plugs. Have a 3100 GM motor and am getting 24 MPG average (driving to work) and that is only average for this car. After seeing some other reviews elsewhere of the cheap electrodes falling off in the engine and they are made in China, I really regret having bought them. If they were made in Japan I believe the quality would have been much better-maybe a higher price, but someone is making a killing on these crappy spark plugs. They supposedly have a better design, just not the quality. I will probably buy some NGK spark plugs and replace them, I just do not feel good about the possibility of the electrode falling off on top of the piston-may end up in the rings and then major problems!! Big waste of my money and time.HHH