Hi, i’m owner of 1986 model Jaguar 3.6 XJS inline 6. I have been working on my car for long time and rescued it mostly but i have a big problem. When i get it first it was really powerfull and agile but after 3 months in mechanic and after it finally get out its like a ship with bike engine. It can’t get over 5000rpm unless i disconnect oxygen sensor and really powerless’ i’m suspecting about vacum but i’m not sure.

Thanks alot for every reply.
and sorry about my english

 

It might be a vacuum leak. Take a can of spray carb cleaner that has the little tube. Try spraying anyplace that has (or is supposed to have) a gasket on the intake side. If there is a leak, you will hear a change in rpm.

 

I solve the vacum leak but its only fixed the acceleration problem and i founded out when i plug out the oxygen sensor the RPM problem is going away but its not the proper fix i think..