It has been almost a year since I had the head replaced on my 98 4.6. The head gasket was replaced 3 times before ford finally put a new head on the passenger side of the engine. Since then I have had to run premium gas to stop the engine from excessive pinging. Even with premium in it, it still pings but not as bad - with regular it pings around town! The engine seems to not have as much power and I think the exhaust manifold is leaking on the same side. The truck ran like new before the head replacement and now it feels loose, old and wore out. What could ford have damaged by replacing the head. Could the valve timing be off? I took the truck back to a dealer while I still had extended warranty and they just kept saying that it is an ignition ping caused by a faulty sensor and they will not know which sensor it is till the engine light comes on.
Any ideas on bringing this motor back to a healthy lifestyle?
Could you please email me with any replies to d.elmer@sympatico.ca
Thank you

 

If you have the patience you can do a search on "pinging". There's thousands of pages of useful info that can help you track down that problem.

Good luck.