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 1,000 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
  1. Home
  2. Questions
  3. Runs fine with the map sensor vacuum line plugged off

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: My engine has a rough idle. It spits, sputters, and stalls out. Could it be a bad injector?

Hi and thanks for contacting Your Mechanic. Yes an injector could cause an engine to spit and sputter or even stall out. Injectors over time can become dirty from the contaminate in the fuel tank that when passed the fuel...

Q: Just bought my car not to long ago with a decent amount of mods done, I cleaned the cold air intake filter and now it makes a pop.

When it comes to these cold air intakes and K&N type filters, the engine air flow is different than the original and your engine control module may not be able to correctly read the amount of air that the engine...

Q: Replaced my tranmission on my 95 k1500,at frist my truck light came on of check gauges,I replaced that now my rpm working right bu

It is not clear if you installed a used transmission or a professionally rebuilt one. If the transmission is used, of course a possibility is it may be faulty and in need of re-building. If the transmission was already rebuilt,...

Related articles

What Causes Hoses to Leak?
While the largest part of your engine is mechanical, hydraulics plays a significant role. You’ll find fluids at work in a number of different areas. Your car's fluids include: Engine oil Transmission...
Rules of the Road For Iowa Drivers
Driving on the roads requires knowledge of the rules, many of which are based on common sense and courtesy. However, even though you know the rules in...
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...