i changed spark plugs in my 2000 chevy Z71 with a 5.3 about a month ago then the other day i was getting on the interstate and when i got up over 60 mph and you put the gas down the motor acts like it shuts off you let off the gas and it goes again not sure whats goin on need help thanks

 

change air and fuel filters

 

^^^^^^x2

 

Could very well be the fuel filter.

 

fuel filter & use some sea-foam to clean the beast - best stuff on earth