i have a 1993 mustang gt, i am planning on replacing the upper manifold gasket this weekend, because i see about 3 inches of it sucked back into the intake, and believe this is the cause of my high idle problem. if anyone has done this job, please inform me of the best possible ways to replace the gasket. the car is completely stock and i havent done a manifold gasket fix yet, so any information is very helpful. im very thankful for any help i may recieve.