I replaced all the spark plugs, replaced the coil on cylinder 4, and the car went back to normal. It was shaking pretty bad especially when you gave it gas. After the replacing the above mentioned parts the car drove fine for 1 night, this morning as i was getting to work it started going in and out of the shakiness. Finally i get to work, and it was full blown shaking again, and the P0304 code is back. Does any one have any helpful advice on this issue?? Please Help.

 

First thing, did you change the correct cylinder?

Bank 1 = passenger side = cylinders 1, 3, 5
Bank 2 = driver side = cylinders 2, 4, 6



A little troubleshooting would be to switch the coil to another cylinder and see if the code follows the problem. If not, make sure the spark plug is not fouling due to oil and such.

It could be a failing fuel injector as well.

 

It was cylinder 4, and yea i changed the coil on the right cylinder and it fixed the problem for 1 night. this morning it was fine, and out of no where started shaking again. The same code for cylinder 4 came out again. Might be the injector then huh? unless the new coil went bad again. I dont know what to think. This car has given me nothing but issues..