1991 Jaguar XJ6 Passing Gear

NO POWER
Check for burned or sticking valves.
Check for incorrect valve clearance.
Ensure fuel system is okay.
Ensure engine compression is okay.
Ensure ignition system is okay.
Check for incorrect camshaft timing.
Check for incorrect octane fuel.
ROUGH/UNSTABLE IDLE
Check for burned or sticking valves.
Check for incorrect valve clearance.
Ensure engine compression is okay.
Check for blown head gasket.
Ensure ignition system is okay.
Ensure fuel system is okay.
Check for an intake air leak. (Idle speed will usually be faster if an intake air leak is present.)
Check for air leaking into or out of exhaust system.