Have a 1999 5.4L that has had a "spark knock" pinging on accleration since about 1000 miles. Is this normal? Should I be concerned? Sounds almost like a manifold leak. I do get less than average gas mileage <10 mpg both hwy and city. Have had mass air flow sensor replaced. Vehicle has 10,000 miles on it now noise is always present on accel. now whirring noise when you release gas pedal (kinda like a metallic winding down noise) Any suggestions?

 

yes .........thats what warrantys are for. Its Not normal and tell the dealer to *fash* it or find the problem. Good luck. They are great trucks and you should be happy.

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97 F-150 4.6 auto, 4x2, 3.55 LS, WMS Velocity tube, K&N, Dynomax Super Turbo exhaust with Echo tube.
Oh yeah, it's Oxford White with crome wheels, Legacy shell & custom grill!

 

Nope. Pinging is not normal. The dealer needs to fix this truck. Your mileage is not normal either, unless you're only doing city driving and flooring it every chance you get.

I have a '99 with the 5.4, 3.55 LS, SC, 4x4, and average close to 12 mpg, almost all city driving with trips averaging less than 5 miles at a time and I love to be the first out when the light turns green.

 

Your problem and the poor mileage is NOT normal at all! Neither my 98 5.4L (or now my 2000 5.4L) made this noise or that bad of fuel mileage.

Only one time did I ever average less than 13 mpg (98 5.4L supercab)...but I drove the crap out of it and it was basically all city driving.

I would really push your dealer hard on this issue and get it fixed under warranty! These really are great trucks.

Best of luck!

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2000 F-150 XLT, 4x2, 5.4L Supercab, Styleside, Black with silver two-tone, 3.55, class III towing package with heavy duty cooling package, overhead console, sliding rear window, keyless entry, dark graphite interior, in dash CD, Pendaliner bedliner, K&N air filter, rubberized undercoating, cabin filtration system, Bugflector II, 5W-30 Mobil 1, engine build 10/4/99