360 2002 Spider Misfire

Hey everyone, I purchased a few months back a 360 Spider that has been sitting for around 5 years. We got everything gone thru except this misfire. It is very light and you can slightly feel it, If I clear the code or turn off the battery switch it will turn off the CEL and misfire goes away for the next 20-30 miles and it starts again. My mechanic has gone thru everything MAF, injectors cleaned, all filter replaced, manifold leak, etc.

According to the PO the Ferrari store in Orlando a couple years back told him it is because it has no cats and Novitec exhaust on it and till then nothing can be done. I ordered the FabSpeed small O2 sensors to see if that helps with the CEL. Any ideas on the misfire, I'm open to tunes if it fixes it but prefer not to.

 

I believe they were replaced but I will have to call my mechanic. I told him everything that is needed top to bottom to do but he may have just tested them. If he did not I'm going to replace them either way so I don't have to in the future. Thanks for the response and idea.

 

Spark Plugs are brand new
Coils I actually just ordered a set
MAF are new and the connector was cleaned
Before starting we drained all the lines, tank, and pumps
I ordered new 02 sensors since it was a pretty cheap part and we will see. We tested the ones in it and they seem good
We did check for the leak but will have him check again.

I have put a lot of miles on it when it is not misfiring and when I am over 3,5000 rpms it goes away and sounds and runs perfect.

 

I made sure I got the real deal ones ordered. The only thing I could think of that I was not able to figure out before is the exhaust vac valve I believe it is called since the exhaust on it now doesn't have the servo.

 

I am going to try that as soon as I can. I had it all the covers off to do it and I did not have the right size cap for it. It left for the shop before I got the caps so we will see when it makes it back.

 

When you say right side, do you mean only plug the right side one?

 

Thank you for the help and hopefully I can pick it up this week and try that.