I am having all 4 cylinders misfire and i have no clue why!! can anyone help?? i did a chevron fuel system cleaner and it didnt work it just made it go for a few days and the CEL light just came back on i also did spark plugs but they also didnt work! Can someone please give me some advice. My car is an 00 with 164k

 

start with spark plugs and coil packs!

 

Get a valve adjustment. That will let you know if you have any engine damage (like mine did).

 

thanks will do!

 

i ran a fuell system cleaner too (redline brand) and after the tank was gone, my CEL came on. changed the plugs and it was good to go.
I wont ever use that stuff again.

 

Well that means redline did its job. Usually you are suppose to change the plugs after you run a fuel system cleaner. Especially if its as strong as the redline one.

 

COILS!

 

I dont want to scare you, but my old s2k had 2 very bent valves which caused misfires in all cylinders