Misfire on 3 and 4. 2001 4.6L F-150
There were a number of problems with V=8 engines in this Series. Some of the sparkplugs would try to leave the engine on their own. You need more testing to know what is wrong.
I will try to explain. The trouble Codes generated by your Onboard computer can be too general to identify a specific part for some problems.
There are 3 causes for a misfire. Fuel, spark, and compression. You can have fuel injectors which are dirty or have bad connections or coils and fail to open consistently. Spark issues are more complicated to diagnose as coils are now attached to individual sparkplugs(some models) and are triggered by Crankshaft and Camshaft sensors. A bad coil-pack feeding each bank of sparkplugs can short out adjacent plugs like #3 and #4.
Compression problems between #3 and #4 cylinders from a bad head gasket can cause misfires.
You can get a loaner test kit for the fuel injectors or use a test light or multi-tester. This will eliminate or confirm the fuel injector circuit as the problem.
There are cylinder balance tests that are non invasive when done with a good scanner. Otherwise removing the sparkplugs will be required to do a compression test.
Sparkplugs leaving the engine: They either unscrew or rip out the sparkplug hole. Loose plugs will misfire. BUT there is a problem with removing sparkplugs on these Series of motors. The factory plugs are 2 pieces welded together. Carbon buildup causes the sparkplugs to come apart as they are removed. Use solvent every 1/4 turn, let set for first 2 twists.
There was a Recall on these motors, but a Mileage limit and a time limit of about 7 Years was imposed. Check Internet for articles about all of these subjects, photos, etc.
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Jan 19, 2013 |
2001 Ford F150 Styleside SuperCrew