4.9 inline 6
New User
Joined: Aug 2000
Posts: 2
Likes: 0
4.9 inline 6
Premium fuel!! Does anyone have any ideas why my engine needs premium fuel? If I burn 87 or 89 octane the engine pings. I have had it tuned several times and mentioned it to the shop to no avail. Tey all claim the egr valve is fine. Help!
Postmaster
Joined: Jul 1999
Posts: 3,172
Likes: 4
4.9 inline 6
Its possible you have some carbon buildup on the tops of the pistons ? I notice my 300 seems to knock if under load when its hot outside (90+F) If I use 92 octane the problem disappears . The knock is not bad with my engine , just enough to notice . I occasionally run some Marvel Mystery Oil Fuel System Treatment , It seems to help reduce the knocking .
