I have a 2004 Frod F150 with 215k miles and the Ford dealer replaced the # 4 plug due to misfire code. the truck ran well for a few miles then started bucking, jumping and shuddering badly. now it's showing the cat insufficient code. One shop says need new phaser kit another shop says check for plugged Cat which I did and no noticable difference in engine. any suggestions would help!!@

 

Moved, you'll get better results here.

My two cents is you have a misfire somewhere and need new plugs, boots and springs all around on all cylinders. Also what engine do you have? I'm assuming the 5.4?

 

Yep! your exactly right I do have the 5.4 engine 3v Triton engine, do you mean new plugs, wires and coils? I don't understand springs. Thanks for the fast response.

 

instead of replacing the Coil on Plug (COP) it is recommended here to get new springs and boots (that connect to your original COPs) and new (the latest version) Motorcraft spark plugs...much cheaper than replacing all the COPs and could be the fix for your 5.4 3V

Bill

 

The ignition is a coil-on-plug design, and unlike many others, the boots are removable from the coils. Inside the boot, is a spring, that connects the plug to the coil. Both can be replaced separately from the coil (much cheaper too). Coils last longer than plugs, but if ran on old (large gap) plugs, the coils can and do wear out from having to jump that gap. Replace plugs every 60k and coils could go 200k miles.

If the plugs have never been changed, plan on a long afternoon, and have the plug extractor tool on-hand. First two generations of plugs are known for breaking beneath the hex head, but the latest SP546s aren't. Slight nickel anti-seize on the threads to prevent galling, dab of dielectric on the inside of the boot. Not hard nor complicated, just requires attention to detail to avoid misfire.

 

Good advice above other than I don't recommend the anti seize but some folks do. The new updated plugs in my opinion shouldn't need it and it could cause a misfire if done wrong. I agree with everything else. This is such a common question I have a canned response for the boots and springs

People on here are probably tired of hearing it but my last 4 or 5 misfires have all be solved with new or cleaned up boots and springs. Cost is under $40 and it sure seems to work for me. Simply remove the coil, remove the boots and spring from the bottom of the coil. Clean the contact point of spring and coil with electrical contact cleaner, put new spring on, dielectric grease on the point where the boot contacts the coil (careful to not get any on the spring or the contact point of the spring and the coil), then very carefully dielectric grease on the bottom end of the boot where it contacts ceramic of the plug but not on the spring so as to not interrupt the connection between the spring and plug, then carefully put the coil back on the plug and do the relearn process.

You'll notice the important of not getting any dielectric grease on anything that is a possible point of electrical current interruption as dielectric grease is non conductive and will lead to a misfire but you do need it to keep moisture out. The boots and spring look like this and are separate form the coils which dont go bad very often.

 

The dealer should not have replaced only one plug, that's issue number one. Replace the rest of the plugs. While you're doing that replace the boots and springs like everyone is saying. These trucks are known to buck and shudder with a misfire.

 

Thanks for the quick response,really appreciate the advice!!

 

Thanks for the quick response, really appreciate the advice!!

 

What ended up being the issue?