Skip the auto shop - Our mechanics make house calls

Q: It will shudder and sometimes die on the highway

asked by on

It starts fine and for the most part runs fine. But I can be driving down the hwy and it will shudder and sometimes just die as I'm driving. And the tach will jump all over the place. Sometimes it just comes back on, other times I have to pull over and start it. The ignition system has recently been replaced. The fuel pump and filters have been replaced. A coworker mentioned something about the intake manifold might have a leak. I'm at my wits end and could use some guidance. You know, other that a 50 cal. Through the block. All the work I mention has been done by a certified mechanic and he is at a loss for what's going on. Thank you for your time.

My car has 158000 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 reads the 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 will often times cause a jerking reaction as the motor starves for fuel or is overloaded with fuel resulting in a momentary flooding condition.

This may also be related to a faulty throttle position sensor. The throttle position sensor reads the position of the throttle plate inside the throttle body in relation to your foot position on the gas pedal. Based upon the inputs from the sensor reading your foot’s position on the pedal, the ECU then makes the direction to supply more or less fuel to the motor. When this sensor is not working properly, this can cause intermittent responses when pressing the gas pedal as you describe. I would suggest having a professional from YourMechanic come to you home to diagnose the shuddering concern and replace any parts that need repair.

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: Had crankshaft sensor replaced, and car is still stalling when slowing down.

Hello, thanks for writing in. If the engine is only stalling when coming to a stop, then it may be a defective crankshaft sensor that was installed or commonly this is caused by a dirty or failing throttle body. I...

Q: Ac/heater, no air flow all of a sudden quit blowing. Blower motor? Fuse?

Hello - as you noted, the first thing to check is the fuse for the HVAC fan of course. The next step is to check to see if the fan works at any speed, or just Low or Medium. If...

Q: Replacement engine running rough.

An engine that sounds like marbles running in a dryer is a classic description of pinging or pre-detonation, this is a sign of major engine malfunction. This in addition to the rough idle and stalling makes me wonder the quality...

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...
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...
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.