Skip the auto shop - Our mechanics make house calls

Q: I am having a problem with degraded acceleration/mileage.

asked by on

My truck hesitates, coughs, and slow to respond to gas pedal inputs. It will accelerate to 55 +/- but very slowly. In park the engine will not go above 4000 rpm and starts to cycle up and down about 800 rpm whem it reaches 4000. It gets a check engine light, (OBD-1 system) and reading the codes points to "higher than anticipated fuel pressures. It also will just quit accelerating while at highway speed and releasing and then pressing down on the gas pedal will usually recover it. I have changed the fuel filter (3times), the fuel pressure regulator, the fuel pump and the fuel injectors. I also recently swapped out the engine brain (PCM) and no improvement. This problem has persisted and gradually gotten worse over the last two years. The truck is now beginning to stall/not start right after it has been driven. What sensor(s)/parts can be causing the problem?

My car has 95560 miles.
My car has an automatic transmission.

I would recommend checking/testing the O2 sensor and the MAF (Mass Air Flow) sensor. When either of these two sensors are not working properly, as you may know, they will send inaccurate signals to the ECM which will then, in turn, be making incorrect changes to the fuel system. It looks like you already had some work done on the car, so it may be smart to get an official diagnosis on the issue before moving forward with another replacement. If you want to have this checked, a certified mechanic, such as one from YourMechanic can come to your home or office to diagnose your acceleration issue and let you know what should be done.

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

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: noise turning off, accelerating

The condenser is a part of the air conditioning system and is similar to the radiator. There is no moving parts on the condenser it is simply a means of refrigerant travel and cool down. You may however be experiencing...

Q: Engine occasionally cuts out while idling at a stoplight and occasionally hesitates and bucks upon acceleration.

There is a issue with the fuel delivery to your engine. It seems as the fuel pump may be failing. Check the fuel pressure on the fuel rail and see if there is at least 30 psi. If the fuel...

Q: engine is missing an surging an idle is rough - 1994 Mazda B4000

Hello. This sounds like you have a lean running engine. This can be from carbon build up on the valves and dirty or clogged injectors. Have the combustion chamber and injectors cleaned. Then see if the engine runs better. If...

Related articles

What Causes Hoses to Leak?
While the largest part of your engine is mechanical, hydraulics plays a significant role. You’ll find fluids at work in a number of different areas. Your car's fluids include: Engine oil Transmission...
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...
P2103 OBD-II Trouble Code: Throttle Actuator Control Motor Circuit High
P2103 means there is a fault with the throttle actuator control motor circuit, likely due to a defective electrical component or part.