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Q: Laboured idling and backfires

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My truck first started with a sputter between 45mph and 55mph while in traffic but if say I was going from 30 to 60 as if getting on the highway it wouldn't do it. Now it has Avery rough idle and it backfires when you take off. And no SES light has been kicked

My car has 154616 miles.
My car has an automatic transmission.

A: This has all the symptoms of a fuel supply ...

This has all the symptoms of a fuel supply issue. Such an issue can cause a lean fuel mixture and backfiring - either from low fuel pressure or inadequate fuel volume. Make sure the fuel pump relay doesn't have a large voltage drop from burned contacts and the fuel pump is getting close to 12 volts (at the pump). Has the fuel filter been changed recently? A clogged filter can cause this behavior. Check your fuel pressure - if low, check the fuel pressure regulator for a worn out fuel pump. A YourMechanic certified technician can come to your home or place of business to perform a Engine Hesitates During Acceleration inspection, provide an accurate assessment of damage, and estimate the cost of repairs.

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