i just replaced the spark plug and the coil for a p0303 on my 05 f150 5.4, but it still gives that light "bucking" feel under light excelleration between 42-53 mph. any suggestions?
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2005 Ford F-150
Question: Why does my 05 f150 5.4 buck and chug under light throttle bewtween 42-52mph?
Answer #1pushrod March 08, 2013, 15:08Master
Bucking is indicative of ignition misfire when in highest gear or converter locked, if auto trans. with light throttle. When you replaced the plugs was any moisture in any of the plug wells? You have another coil breaking down, the BEST way to fix this is to replace ALL of the coils with Motocraft parts but can be pricey! Any problem changing any of the spark plugs? Have a cylinder contribution test, while driving, done. A real scanner can do this. Test will show problem cyl. without waiting for the light to come on with a code.
Use Motorcraft parts on your Ford, coil(s) and spark plugs. Some parts stores carry genuine Motorcraft parts, Advance Auto does here in Va.
Save you some bucks as opposed to dealer! Check around.
Answer #2rpclements March 08, 2013, 19:48Journeyman
May possibly be fuel injector #3