The other night my car (07 GT/CS)was down to 50 miles until empty so I filled it up at Citgo (usally only use Mobil 87 octane). I drove it about 7 miles the check engine light came on and the car was misfiring. So the next day I had a buddy run the code & it said cylinder #7 was misfiring. Needed to replace both the #7 plug & coil. It now runs great. Was it the gas, a common occurence, will I need to eplace all plugs & coils? I have 59k for miles, gas mileage is good about 18 around town & 24 on the HWY.

Thanks for any input

 

It was probably just on it's way out, I had to replace the coil on cyl # 3 at 20k miles, that's it just one bad coil.
They usually last a VERY long time with no issues, you don't need to replace anything else.