Skip the auto shop - Our mechanics make house calls

Q: Runs fine with the map sensor vacuum line plugged off

asked by on

If I leave the map sensor connected the enine load up and stalls. I already replaced the tps,map sensor,injectors, distributer , fuel pump and filter, ecm.

My car has 180000 miles.
My car has an automatic transmission.

Hello, the map sensor is an input of engine load. When the map sensor is disconnected it will set a fault code which is emission base and check engine will come on,this cause the system to go into a default mode. It uses engine vacuum as a measurement of that load. There is also an electronic aspect - the map sensor uses a five volt reference (0-5 volts). Zero volts would represent low engine load and 5 volts would be high load. You need the correct vacuum at the sensor to operate. Things that could affect this are having a vacuum line that’s plugged to the sensor or blocked at the intake manifold. There would be several steps to take in a diagnosis process. The overall health of the engine can create false input information to the computer (ECM). If you’d like, a certified technician from YourMechanic can come to your location to diagnose the issue.

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: Gasoline smell in a 2003 Vauxhall Corsa

If it's unburnt gasoline, maybe the spark plug wires are not working right. A lot of times the fuel injectors can be dirty and then instead of spraying a conical shape of fluid, it would be lumpy and won't burn...

Q: Car lost all power after downshifting to go uphill

Hello! Although the Check Engine Light has been on before a new issue may have occurred, I would suggest hooking a scan tool up to the vehicle and retrieving the OBD2 codes. The problem you're having should almost certainly set...

Q: My 1996 2wd v6 chevy 1500 silverado is backfirng, has little black chunks spit from exhaust pipe and shakes pretty bad when driven

Hi Dawn. Thanks for contacting us today. Usually the symptoms you are describing are caused by a clogged or damaged catalytic converter, a vacuum leak or an exhaust leak. It's also possible that your fuel system is clogged with excessive...

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...
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.
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.