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Mike V.
Mike V., Auto Service Technician
Category: Ford
Satisfied Customers: 25197
Experience:  25 years experience on all makes and models, Licensed NYS Inspector.
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P0303 code on my Econoline 4.2 L V6. There is noticeable

Customer Question

P0303 code on my Econoline 4.2 L V6. There is noticeable sputtering as I accelerate at low speed once the engine has warmed up, not really noticeable at higher speeds. The plug fires. I replaced it and put the old one in the plug wire and laid it on the engine, started it and saw that it was sparking. The injector makes its clicking noise so I know it's trying to work. The plug that I replaced seemed not to have discolored much when compared to another plug, making me suspect that there wasn't much exploding in that cylinder. I'm wondering what to try next.
JA: Where exactly do you think the noise is coming from? And how long has this been going on?
Customer: I used a long screwdriver as a stethoscope to hear if the injector was working.
JA: What is the model/year of your Ford?
Customer: It's a 1999 e150.
JA: Are you fixing your E150 yourself? What have you tried so far?
Customer: I did the troubleshooting I described in the first paragraph.
JA: Anything else you want the mechanic to know before I connect you?
Customer: I don't think so.
Submitted: 3 months ago.
Category: Ford
Expert:  Mike V. replied 3 months ago.

Thank you for your question!
My name is ***** ***** give me a moment to review your question and respond with the assistance you need!

Expert:  Mike V. replied 3 months ago.

Ok, you know the injector is firing, but you don't know if it's firing properly. What I would do is take #3 injector and swap it with the one next to it and see if the misfire moves with the injector. If it does, then oyu know it's an injector issue.
​Before you do that however, check for intake manifold gasket leaks by spraying some carb cleaner along the intake with the engine running, if the skip stops or if the idle increases then you have a leak.
​Also, and I would probably do this before swapping the injectors, check the engine compression on #3 and compare it to #4. The carb cleaner check and the compression test will be easier then swapping the injector.
Please let me know what more I can do to assist you today. Also, please be kind and remember to rate my answer using the stars at the top of the page. Just Answer does not compensate me for my time and resources. Follow up questions are included in the price of your question. If you are using the free trial, or have a subscription a rating is still required.
Thank you so much!

Expert:  Mike V. replied 3 months ago.

Do you need more help with this?