Skip the auto shop - Our mechanics make house calls

Q: My 1993 GMC Sierra will barely go past 40mph

asked by on

Hey, i have a 1993 gmc sierra with 256k on it right now. And it will act like it will barley wanna go past 40 mph and when it does you cant hold a speed at all without the rpms going to 2,000 and sometimes 2,500

My car has 256000 miles.
My car has an automatic transmission.

This may be a sign of a dirty or failing mass air flow sensor. The mass air flow sensor is a unit in the intake system that monitors air intake as it is mixed with fuel prior to being injected into the motor. When this fails, this can cause an imbalanced air/fuel load to be supplied to the motor which results in an over fueling or under fueling situation depending on the conditions. This is what causes the hesitation or loss of power you describe. This can also cause the engine to struggle to idle for the same reason. I would suggest having a professional from YourMechanic come to your home to diagnose your mass air flow sensor.

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: Jerking apon acceleration

Further diagnosis as to why the check engine light is on should be done. A repeat code for the knock sensor may be caused by a wiring issue or even due to a faulty pcm (power control module). Odds are...

Q: First the service traction control message came up and after it was the service stabilitrak. Two days later the reduced engine power light came on.

Hi there. There is an issue with the traction control system and it may be active with the loss of power happens. Check the brake system for any loose or damaged wheel speed sensors. The traction control system works when...

Q: recently my Safari started "hesitating" or " shifting" roughly when shifting at low speeds. doesn't do it all the time

Hi there. Many electronically controlled transmissions are computer controlled. With that said, the input signals for the engine can have a direct affect on the transmission behavior. Do no rely on scan tool recommendations because it is just that, a...

Related articles

P0052 OBD-II Trouble Code: HO2S Heater Control Circuit High (Bank 2 Sensor 1)
P0052 code definition HO2S Heater Control Circuit High (Bank 2 Sensor 1) What the...
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...