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Super Mechanic
Super Mechanic, ASE Certified Technician
Category: Ford
Satisfied Customers: 16821
Experience:  GM, Ford, Chrysler, nissan, mazda...30 years. ASE Master, troubleshooter
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It runs good until you get to 55mph then jumps and jerks

Customer Question

it runs good until you get to 55mph then jumps and jerks like its starting to miss on a plug or two once it is in park it runs at a idle smooth for a few seconds them it will miss then run good then miss more
JA: What is the make/model/year of your car?
Customer: 2003 ford lariat 4x4 w/ 235,000 miles
JA: Are you fixing your vehicle yourself? What have you tried so far?
Customer: just put seafoam in gas, this worked good for the last year when it would do this but now seafoam don't work on it
JA: Has the vehicle turned into a gas hog? And how does it start -- same as usual?
Customer: it does use a good bit of gas but it cranks very good as usual, do you think a new fuel filter is needed
JA: Anything else you want the mechanic to know before I connect you?
Customer: no
Submitted: 4 days ago.
Category: Ford
Expert:  Super Mechanic replied 4 days ago.

Hello and welcome. My name is ***** ***** you for visiting the site, I am reviewing your question and will reply shortly, thanks.

Expert:  Super Mechanic replied 4 days ago.

Let me just say that any money that you paid, or if you have a subscription, that money stays in your account until the answers are rated, (positive) regardless of how fast or how long it may take to get finished. You can FOLLOW UP AT ANYTIME, even after rating.


You will want to check the fuel pressure to see if it is too low. Also that the filter is not restricting the flow of fuel.


Also the plugs and coil boots, to be sure that none of them are loosing spark.



If they are both ok, then you will want to take a sample of the fuel to be sure that it’s not contaminated.


Please don’t forget to rate the answer, **** THAT IS THE ONLY WAY I GET PAID **** if you need any more on it, I will be here. Thanks