OBII codes on my car

Question

I have a 2001 Mitsubishi Galant.

I got these codes when they hooked it up: P0112-mass air flow sensor, P0115-coolant temp. sensor, P0134-o2 sensor, P0171 system too lean, and P0303-cylinder 3 misfire

With these codes, is this the problem why my car is sluggish and dont want to get the power it should? I want some suggestions because I have to bring it to the shop and I dont want to be screwed out of my money if it is something else.

Answer 1

Yes all these codes can make it run sluggish. Clean the m sensor with break cleaner,just take it off and spray inside good and reconnect it,if coolant level is good then the sensor out side the resoivor is going bad,O2 sensor can make the po171 show up,change it then disconnect the positive battery cable for about 60 seconds and reconnect it,then see what the scanner(auto zone ) will check for free pulls up.

Answer 2

Let the shop diagnose it and give you a written estimate. Don't tell them you know what's needed. The shop should guarantee the work. Take it to a couple of places before you get it done, unless you really trust the first one.

Answer 3

codes are prioritized, hard faults/current codes and history codes. the Mass air flow is probably your problem. It will cause most of your other codes to trigger. your new code is a evap. emission code usually will not cause a running issue.

Answer 4

It IS the O2 sensor!!!!!!!!!!!!! the P0134 code means "O2 Sensor Circuit No Activity Detected (Bank 1 Sensor 1) ". The O2 sensor is either unplugged,  damaged or the wires to it are cut which can happen due to road debris. Fix it now because it can damage your catalytic converter(very expensive), as may be happening with your P0421 code which is "Warm Up Catalyst Efficiency Below Threshold (Bank 1) " It can also cause sluggish running, bad gas mileage, misfire, engine too lean and every thing else you said.

A mass airflow problem will NOT cause a P0421 code as others have suggested.