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rpmdiag, Tech and Instructor
Category: Ford
Satisfied Customers: 7753
Experience:  Since 1975
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I have a 2002 F-250 SD 5.4 V8 gas with 238,000 miles on it.

Customer Question

I have a 2002 F-250 SD 5.4 V8 gas with 238,000 miles on it. I had spark plugs replaced at local dealer at 152,000 miles. I'm currently having misfire codes on #4 and #8 cylinders. I know that's a lot of miles on a gas engine and 86,000 miles since spark plug replacement.
Do you think spark plugs are the culprit or maybe the coils on both cylinders, injectors? Probably time for spark plugs again anyway and would be cheapest try. I can't afford to replace truck at this time and it's been a good one.
Submitted: 1 year ago.
Category: Ford
Expert:  rpmdiag replied 1 year ago.

Hi, I’m Ron and I’ll be helping you today.
Before we get started though, Please understand that I don't know
your skill level or tools you have to assist us. Also understand that
I can't see, smell, hear, or touch the vehicle either, so patience is
appreciated. JA is a great Q/A site, but it does NOT replace a
repair shop.
My goal is to make you happy and get a great rating in return for
my time. Sometimes I have to give you bad news that I know you
didn’t want to hear, so please don’t shoot the messenger.

You've been very lucky so far. I would start with new plugs and go from there. the coils do give problems now and then, but the plugs take a beating everyday. We'll address the other items if we need to later on.

Thanks, Ron