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F150 Won’t Stay Running: Top 5 Reasons and How to Fix

F150 Won’t Stay Running: Top 5 Reasons and How to Fix

It can be quite dangerous if you take your truck out for a drive and it unexpectedly cuts out after a few minutes on the road. Narrowing down the cause when your F150 won’t stay running can be daunting, and taking it to the shop can get pricey.

Luckily, there are ways to tackle the various reasons why your F150 won’t stay running. Keep reading to discover how to diagnose the issue and achieve fixes for each possibility. You’ll also learn about preventative measures to ensure your truck is in tip-top shape and safe on the road.

Top 5 Reasons Your F150 Won’t Stay Running

Thankfully you don’t have to be a certified mechanic to pinpoint where your truck might be having issues causing it to cut out after running for a short time. It may take some time and energy to resolve the problem, but what you pay for in those resources, you’ll save in labor costs if you can fix it yourself.

The average cost to diagnose a car is $65 to $100. These reasons and fixes can potentially keep that hard-earned money in your wallet.

Fuel System: Fuel Pump

Your fuel system is the top contender for your F150’s inability to stay running. The fuel system consists of several parts: carburetors, injectors, fuel pumps, etc. You’ll need to diagnose each to find the culprit. Let’s start with the fuel pump.

The fuel pump distributes fuel to the injectors, dispersing it to the engine. If your fuel pressure is low, it is likely the fuel pump that needs to be repaired or replaced.

  • The fuel pump should be replaced at around 100,000 miles or so.
  • However, some have been known to last at least 200,000 miles.

First, perform your fuel pressure test. Install your pressure gauge first. Turn on your car and let it idle. Your pressure gauge should record a reading. Compare your reading to the Ford manufacturer’s specifications for the F150.

  • Now move on to perform a timed fuel test.
  • You will see how much fuel you can get out of the vehicle in five seconds.
  • The best tool to use for this is a glass graduated cylinder.
  • Once you have your measurement of fuel, compare your volume to the Ford manufacturer’s specifications for the F150.

Replacing a fuel pump can be dangerous, especially with a full gas tank, as fuel is flammable. If you decide to tackle the replacement yourself, take the necessary precautions, including having a fire extinguisher. It may be worth the peace of mind to shop around and take it in for repair or replacement.

To avoid the premature breakdown of your fuel pump, change your fuel filter to the cadence the Ford manufacturer recommends.

  • Be sure to use quality fuel and never allow the tank to drop below half a tank.
  • Don’t get gas at the same time or right after a fuel station is receiving fuel.
  • Dirt and deposits get stirred up and may make it past the fuel filter.

Fuel System: Fuel Filter and Fuel Injectors

Fuel filters and injectors can get clogged by impurities in the fuel and debris, including dust particles and other contaminants. Both parts require regular maintenance. Fuel filters should be changed every 20,000 to 40,000 miles, and a fuel injector should be cleaned every 60,000 to 90,000 miles.

With fuel filters, it’s best to change them when they are due to be replaced. You can look at their appearance to see if they’ve sustained any damage or look for gumminess or dirt, but it may be best to take out the fuel filter and see if the remaining gas flows freely.

To test for faulty fuel injectors, start your engine and allow your vehicle to idle. Touch the end of a metal screwdriver to the injector and place your ear on the opposite end. If you hear a clicking sound, the injector is working properly; if not, it will need to be cleaned.

Fuel System: Carburetor

Your vehicle’s carburetor mixes fuel and air to allow for proper fuel combustion in the engine. If the stalling is due to a faulty carburetor, it might need an adjustment. If an adjustment doesn’t resolve the issue, the mixture of fuel and air either has too much gas (rich) or not enough gas (lean). (source)

The way to diagnose the issue is by spraying carburetor cleaning spray into the carburetor’s throat while the engine is idling.

  • If the idling smoothes, you have a lean condition.
  • If it gets rougher, your condition is rich.
  • Adjust the mixture screw according to its condition.
  • If it’s rich, turn it all the way in.
  • If it’s lean, turn it out 3 to 5 turns.

If these adjustments do not resolve the issue, you may need to rebuild your carburetor, or you could have a vacuum leak.

Carburetor Vacuum Leak

A vacuum leak can cause too much air in the engine resulting in the vehicle stalling. Like the carburetor check, you’ll test for a vacuum leak when the engine is warm and idling.

Spray the cleaning spray into the carburetor, then begin lowering your idle by backing off the idle set screw. Continue using the spray as you back off until the screw no longer touches the throttle linkage. Your car should stall or dramatically reduce RPMs. (source)

  • If the RPM stays high, check the throttle to ensure it’s closing properly.
  • If it is, then the air source comes from a vacuum leak.
  • Check each vacuum hose with a pair of needle-nose pliers.
  • Squeeze each hose one at a time, checking for an RPM change or the idling to smooth out.
  • If this occurs, the hose or connected component needs to be replaced.

If none of the hoses are the source, cautiously use a flammable spray to check around the intake manifold gasket, brake booster hose, solenoids, actuators, and throttle body.

This method has risks and could cause your engine to catch on fire, so the recommendation is to use proper tools or take the vehicle to a professional. If you use this method, take safety precautions, including having a fire extinguisher.


Some honorable mentions of other possible causes of your F150 not staying running are the alternator, camshaft sensor, or your battery. When in doubt, take your vehicle to a professional to be diagnosed and repaired. Regular maintenance according to the Ford manufacturer’s specifications will help avoid these issues.

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