Just replaced upper valve cover gaskets, intake manifold gaskets and 6 spark plugs. It stopped oil leak and seemed to go well. Before putting intake manifold back on I sprayed seafoam inside and than rinsed out with water after letting it sit for awhile. After letting it dry or at least seemed dry I put it back on and started car. It idles fairly gentle, better than before work but is chugging off and on when I drive, during acceleration or even revving while idle. Did I possibly not let manifold dry all the way? Seafoam a bad idea? Could I have installed spark plugs wrong? or to tight? THank you for any help!

 

Maybe the hose under all that lot has perished, as they do with age.

 

it would be just my luck that would happen after I put it all back together.
Would that make engine shake and run like crap?

 

Why yes, yes it will edan..

Look in the first paragraph in the following link for Gus's link to his Jag repair page.
https://www.jaguarforums.com/forum/s...ics-faq-52720/