Q: low idle runs better when map sensor is unplugged boggs down

asked by on February 23, 2017

i have a 93 chevy full size blazer. i replaced the fuel pump, fuel filter, distributor, cap and rotor, plugs and wires, idle air controle valve, map sesnor, coolant temp sensor, throttle positioning sensor, and egr seloniod. when i slightly give it gas it tries to bogg down and stall unless i feed it more gas. it runs great on the highway but when pulling out of a parking spot or driving slow it spits and sputters.

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

Hello. Unplugging a sensor to see if it will make any difference is an old-fashioned way to test a sensor on an engine. If the vehicle runs better without the sensor unplugged it most likely means that the sensor is faulty. Of course now there are more modern ways of testing a sensor such as with a multimeter or scan tool. I suggest that you have a technician inspect your manifold absolute pressure sensor with either a scan tool or multimeter to help further diagnose your issue. Being that you already replaced the map sensor the new one may be faulty or there’s a wiring issue present. You’re able to schedule an appointment and find a technician that will diagnose your issue here

https://www.yourmechanic.com/services/car-idle-is-rough-inspection

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