I am experiencing a noise like valves rattling or spark knocking when a start uphill on the freeway at about 70MPH. I have a 99 Extended Cab XLT with 5.4L and OD Automatic Transmission. Down shifting doesn't illeviate the problem. Is anybody else experiencing this? It is irritating. Is it normal?

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White
1999 F150 XLT Extended Cab
Sony CDX 424 RF CD Changer
5.4L With Tow Package
Stock Except for a K&N Filter

Roll Tide!!

 

I'm almost convinced its normal. I've seen other folks post this symptom, only to have the dealer say its normal..
I plan to take mine in to see what the dealer says..
btw: I've heard this described as, during acceleration:
- spark knock
- VW Beetle sound
- light pinging
- noisy valves
- sounds like a diesel
- hissing

Y2K F250 XLT SC 4x2 5.4L 5sp 4.10LS

 

The 1998 Owner's manual, pg. 187, under "Octane recommendations" and Page 211 in the 2000 Owner's manual under the same section states:

" Do not be concerned if your vehicle somtimes knocks lightly. However, if it knocks heavily under most driving conditions on fuel with the recommended octane, see your dealer..to prevent any engine damage."

If you are using 87 Octane...you could go to 89 and see if this helps.

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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, 4 wheel disk ABS, 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