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.

A: This may be a sign of a dirty or failing ma...

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・Save up to 30%

Get a quote

What others are asking

Q: Engine not getting fuel.

Older vehicles such as your Suburban tend to be a little easier to diagnose. If you suspect a lack of fuel to be your issue you may very well be correct. One trick you can try yourself to verify this...

Q: no acceleration power

You did not mention replacing the fuel filter and checking the fuel pressure. If the fuel pressure is okay, then the computer should be scanned to see if there are codes and correct sensor readings. The MAF (mass airflow sensor)...

Q: Alarm going off when starting

This will generally occur when the key is not recognized by the vehicle. Try another key if one is available. If the vehicle is still having an issue with he other key the anti-theft system will need to be accessed...

Related articles

How Long Does a Heater Control Valve Last?
Keeping the right amount of coolant in a car is essential in keeping the engine at the right temperature. Failing to have the right amount of coolant or even bad elements...
P2428 OBD-II Trouble Code: Exhaust Gas Temperature Too High Bank 1
P2428 code definition A P2428 trouble code signifies that the PCM has detected a problem in the exhaust gas temperature sensor circuit in bank 1, which subsequently contains the number one...
How Much Does a Mechanic Make in Vermont?
Automotive technician jobs in Vermont have an average mechanic salary of $37k, with some mechanics earning a salary of $53k.