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Ron Z.
Ron Z., - Ford Tech -
Category: Ford
Satisfied Customers: 18874
Experience:  18+yrs experience. State Inspector & Ford Diagnostics/Repair
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I have a 2003 ford expedition and its miss firing should i

Customer Question

i have a 2003 ford expedition and its miss firing should i replace al lof my engine coils
Submitted: 1 year ago.
Category: Ford
Expert:  Ron Z. replied 1 year ago.

Did you happen to have any of the "p-codes" scanned from the on-board computer?

Customer: replied 1 year ago.
this is what the mechanic is telling me and he replaced 1 and 5 but its still miss firing
Expert:  Ron Z. replied 1 year ago.

Can I have the p-code(s) that were scanned?

Customer: replied 1 year ago.
unfortunately i dont have them you have a shop that i can bring my truck to so that you repair it for me
Expert:  Ron Z. replied 1 year ago.

We do not have an actual "shop". We are simply consultants.

Ok- unfortunately, with the p-codes I am at a little disadvantage as I do not have all the info the current mechanic has, however, I think I can give you a little insight here...

The ignition coils for this vehicle are in fact, very well-known, high fail rate items. However, if the p-codes pointed to specific cylinder (in this case 1 and 5) then there is absolutely no need to replace "all" the ignition coils. Replacing just the faulty ones is perfectly fine. If the misfire still remains after the coil replacement, then there are a few things that will need to be checked and tested. The electrical connector and wire harness to these coils will need to be inspected and tested. The fuel injectors for these cylinder will need to be tested. An intake air leak around these cylinders will need to be done (also a common problem on these engines). And lastly, a cylinder compression test. If you'd like to have the p-codes scanned, you can have this done for FREE at most local big-chain parts stores, like AutoZone (except in California). If the codes still point to 1 and 5, then as stated above, the coil was not the problem to begin with, and the items mentioned will need to be tested. If the p-codes come back as anything besides 1 and 5 cylinder misfires, then I'd need those codes to better tell you how to proceed. If my answer has helped you, please help me by leaving a rating or accepting my answer so I may be credited. Rating or accepting my answer does not cost you extra. It allows me to be credited for my work. Please rate or accept. You can ask follow-up questions after you rate or accept.

Expert:  Ron Z. replied 1 year ago.