Help need opinion ?? Cali T

I have had a really pesty problem w my Cali T . I get a cel 304 - miss fire cylinder 4 on when I punch it down at high RPM . We swapped the coils from 4 to cylinder 1 . No change . The tech said he also moved plugs - no change . They also moved left bank injector rail to right side . ( I am not totally sure they traded plugs & frame rails .
They send me a picture of bore scope on cylinder 4 and said the problem is a scarred cylinder wall at top of 4 . I got to thinking though and could that simply be where the rings stop at top dead center??
If they are right , the cure obviously would be VERY expense . What do you think ? Please help . Thanks james
Image Unavailable, Please Login

 

Ps I forget to mention , car runs great , idles fine - doesn’t stumble at hi rpm’s when CEL misfire light comes on thanks james in San Antonio Tx

 

Hmmm thanks so much . No they didn’t do compression test . I am having them swap right @ left injection rails first to see if problem moved. If not then compression test. Do you think the carbon at the top of the cylinder could be the problem ? Thanks , james

 

Thanks , me thinks I need to take it to Houston Ferrari-let them diagnose it . Thanks Wade