Skip the auto shop - Our mechanics make house calls

Q: Why does my truck misfire in third gear 1999 Ford F-150

asked by on

Cleaned the maf sensor. Installed new coil bank. New throttle position sensor. Changed fuel filter. Changed air filter.New spark plugs. Still it misfired in 3rd gear when accelerating. Could the problem be the fuel pump. Low pressure output? Please help any other ideas?

My car has 238000 miles.
My car has a manual transmission.

Hello If you are getting a random misfire code at higher speeds then you may have a fuel system issue or an air flow problem. I would usually test the fuel pressure to make sure that the pump is fine and then test the air flow meter to make sure that it is putting out the right signal. I would then also check the exhaust to see if the catalytic converter is restricted as that would also cause this to occur. If you are going to have this repaired, consider YourMechanic, as a certified mechanic can come to you to [diagnose why the engine is misfiring] https://www.yourmechanic.com/services/engine-is-misfiring-inspection

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Ask a Mechanic
(100% Free)

Have a car question? Get free advice from our top-rated mechanics.

Ask A Mechanic
Over 10,000 questions answered!

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: How do I change from two step to one step door unlocking?

Your truck automatically uses two steps to unlock the doors. The two step door unlocking can be switched to one step door unlocking at any time. To switch to one step door unlocking. Hold down both the Lock and...

Q: How do you jump off the battery?

While your car includes a number of safety systems designed to help prevent the possibility of being stranded with a dead battery, it’s still possible. Here’s what you need to know to get your car jump-started: Put the car...

Q: Code 1349 P

Hey there. Try having the compression checked for each cylinder. I have had experiences where this code pops up due to a lack of compression from a burned exhaust valve. Also, are you using the right fuel? Using inferior fuel...

Related articles

How Long Does a Distributor O Ring Last?
The distributor is part of the ignition system in your vehicle and its purpose is to route high voltage from the ignition coil to the spark plug. The spark plug then...
P0240 OBD-II Trouble Code: Turbocharger Boost Sensor B Circuit Range/Performance
P0240 code definition Turbocharger Boost Sensor B Circuit Range/Performance What the P0240 code means P0240 is an OBD-II generic code triggered when the Engine Control Module (ECM) detects the intake boost...
What are the Car Pool Rules in Hawaii?
Hawaii is widely regarded as a land of vacation and relaxation, and as such, its scenic roads and routes are far better known than the state’s freeways. But, as with all...