My car gave out

I had a mechanic replace my VCG today along with a new ignition coil (cylinder #2) - please note I replaced my spark plugs 3 weeks ago ( all 6 )

As I was driving I noticed some misfires but didn't give much thought to it. I drove my car about a good 25 miles on the freeway from Fullerton to Irvine. 3 hours later I started up my car but it kept stalling and misfiring. I tried the second time and it turned on. I drove for about a min and stopped at a stop sign. As I pressed the gas. (My check engine light came on) my car just gave out and turned off completely. I waited for a minute and I was able to turn my car on and turn around to go back home normally ( the check engine light didnt come on)

I parked the car, opened the hood, and turned my car on again. This time it kept doing the misfire/odd startup - it felt weak and seemed like it was struggling to gain power. It will rev up on its own and rev down. After an hour my car wouldnt start at all. The tow truck guy had to dag my car on the flatbed.

I have gas in the car, there are no oil leaks, I didnt hear a hissing sound or a rattling sound.

Could there be a problem w. My spark plugs or that the VCG wasnt installed properly?