Ford F-250: Why is My Truck Hesitating?

Hesitation, or a lack of throttle response, is a symptom with many causes. We list the common ones for gasoline and diesel Ford F-250's below.

By Pizzaman711 - November 20, 2014

This article applies to the Ford F-250, F-350 Super Duty (2004-2014).

Hesitation and power loss are signs that something is wrong, and if left unfixed, can get worse. Usually, regular maintenance will prevent any problems, but like anything else sometimes things slip by or just fail prematurely. It's important to fix the problem as soon as it's discovered so that it won't lead to more expensive problems down the road.

Materials Needed

  • DTC code scanner
  • Socket set

Step 1 - Pull DTC codes (gas and diesel)

When troubleshooting, the first thing you should always do is check to see if any trouble codes have been logged in the truck. These DTC codes can really help narrow down the search for a problem. The OBD-II port to read the codes from will be located under the dash on the driver's side. If you don't have a DTC code reader, most auto parts stores will read the codes for you for free. The code in the form you receive it from the scanner will be meaningless, so you'll need to do your research to find out exactly what the code means. If you can't find it online, a call to your local dealer will be helpful.

Figure 1. An OBD-II code scanner.

Step 2 - Check fluids and filters (gas and diesel)

The two key things an engine needs to run are air and fuel; if one of those is being constricted, then power loss can occur.

  • Check the air filter: if it's dirty, clogged, or just older than 10-15k miles, it needs to be cleaned or replaced.
  • Check coolant level and condition: an improperly cooled motor can lead to expensive problems.
  • Check oil level and condition: overtime oil breaks down and loses its lubricating properties.
  • Check transmission fluid level and condition: if the fluid is low or in poor shape, it can cause the transmission to slip or not engage properly.
  • Check the fuel filter: if it's clogged it will need to be replaced.

Step 3 - Check spark plugs (gas)

Faulty spark plugs can cause the motor to misfire which gives the symptoms of hesitation; however, this is a pretty noticeable problem when it happens. You need to check both the plug's condition and the gap on it. If the gap is too far apart, it can cause misfiring even on a perfectly good plug. In addition to the plugs, faulty wires or coil packs can cause misfires as well. You may need to use an ohm meter to do testing on wires and packs.

Figure 2. Old plug vs. new.

Step 4 - Clean mass air flow sensor (gas)

A dirty mass air flow (MAF) sensor can send improper signals about the air level to the computer. Normally a lean or rich code is associated with a dirty MAF. To clean it, you'll need to unbolt it from the air intake and then wipe down the sensor with electronics cleaner.

Figure 3. Mass Air Flow Sensor removed from intake tubing.

Step 5 - Performance tuner (gas)

From the factory, some motors just have poor throttle response, which gives the feeling of hesitation when stepping on the gas pedal. A performance tuner can not only improve throttle response, but can improve the overall performance. Going with a tuner that allows for custom tunes to be loaded versus one with canned (preset) tunes is highly recommended. Preset tunes are made to cover a wide range of vehicles, so while they'll offer some improvement; you won't see any drastic improvements due to every truck being slightly different. Custom tunes open up a whole new area of performance gains as you can have it custom set for everything that you've added to the truck, like cold air intakes, exhaust, etc.

Figure 4. Edge Performance Tuner.

Step 6 - Check charging pipe (diesel)

If the hesitation is occurring when building boost, you may have a leaky up-pipe. The easiest way to check is to look for soot on it; any soot is a sign there's a leak somewhere. Replacement on these isn't easy so it's recommended to replace them with a set of bellowed up-pipes to help prevent the problem from happening again. The red arrows in the figure below point to the two up-pipes on the 6.4L Diesel.

Figure 10. Up-pipes route exhaust gas to the turbo.

Step 7 - Check DPF (diesel)

A clogged diesel particulate filter (DPF) can cause soot to back up in the motor, which can lead to very expensive repairs. It's always important to keep it clean to keep the soot from flowing through the system. When it begins to back up it can lead to hesitation and then eventually damaged fuel injectors, damaged turbo, and a damaged EGR.

Figure 11. Clogged exhaust piping.

Step 8 - Replace throttle position sensor (diesel)

A bad TPS can lead to hesitation and odd acceleration patterns. Newer vehicles are going to have a TPS tell the computer when to add more fuel versus having a direct connection between the injectors and the pedal. When a TPS begins to go bad, it may not pick up all the signals or may be delayed, leading to hesitation when trying to accelerate. For the most part these aren't serviceable and will need to be replaced.

Figure 12. Throttle body and throttle position sensor.

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