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.

A: I would recommend checking/testing the O2 s...

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

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: I got rust in my engine is there a way to get rid of it in truck?

The rear ABS sensor is mounted in the top of the rear differential. I am not sure if your question is about rust in your engine? Can you clarify the question? You also mention a problem about the engine...

Q: My transmission seems to be slipping or something else...?

This may be a simple adjustment to the throttle kick down on the transmission. It may be out of adjustment or there may be a problem with the shift solenoids in the transmission. The kick down is a simple adjustment...

Q: I have a 2004 Buick Rendevouz that doesn't want to start. At first, it had a hesitation problem and it died at low rp

The camshaft position sensor will make the engine run but poorly. Check the crankshaft position sensor to see if its damaged or unplugged. A damaged crankshaft position sensor will cause a no spark condition. If you need further assistance with...

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...
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.