Skip the auto shop - Our mechanics make house calls

Q: 1999 Mitsubishi Eclipse running rich and stalling at idle

asked by on

I have a 1999 Mitsubishi Eclipse. It's running rich and stalls occasionally at idle. I've done a fuel pressure test and it looked fine, which I believe can rule out a leak in the injector. There is no MAF sensor and the throttle position sensor is reading 13% at idle. What is my next step?

A: First of all, you've got to realize tha...

First of all, you've got to realize that, although those technically don't have a MAF mass air flow sensor, those use what is called a Karman vortex sensor. Those sensors are notorious for going bad on Mitsubishis.

They do the same thing--they measure how much air is going into the engine to tell the computer how much fuel is going to put into a fuel injector. You will want a certified technician, such as one from YourMechanic, to come and hook up a high-level scan tool and analyze the Karman vortex sensor.

That can easily be what the problem is. If it is not that, running rich either means that you are getting way too much fuel, or you are not getting enough air. So, you'd want to check and see if you have any air restriction on the intake.

Something as pesky as an air clogged air filter can do that. You can also have a problem with the fuel filter. You might check it, to see if the fuel filter is clogged or anything like that. But, your throttle position sensor is reading 13% at idle. That is actually a little bit high. If it's saying that it's a little more open than it is, then the computer will send more fuel to the car and that will make it run rich. That a lot of times can cause that problem too. That's a relatively common thing that happens to those cars. I recommend getting the car checked and having a qualified technician diagnose your stalling issue. That way, you can be more certain about what repair is needed.

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・Save up to 30%

Get a quote

What others are asking

Q: Alarm preventing from starting

Your Mitsubishi Montero has several different alarm options that are factory installed. In order to repair or disable the alarm for inspection, the vehicle needs to be seen by the Mitsubishi dealership. hey have the dealer specific scanners that are...

Q: Maintaing power in a 1968 Charger

That baby was made for high-test gas. So, you have to buy the best gas you can find. I say use the Shell V-power if you live in the United States. That seems to be the best gasoline for those...

Q: Radiator doesn't cycle even though new.

It is possible that there is an air pocket in your cooling system. This is not uncommon. The air just needs to be expelled. If I may ask, did you replace the radiator due to a leak or because the...

Related articles

P0052 OBD-II Trouble Code: HO2S Heater Control Circuit High (Bank 2 Sensor 1)
P0052 code definition HO2S Heater Control Circuit High (Bank 2 Sensor 1) What the P0052 code means This code is seen when the Engine Control Module (ECM) tries to control the...
P2428 OBD-II Trouble Code: Exhaust Gas Temperature Too High Bank 1
P2428 code definition A P2428 trouble code signifies that the PCM has detected a problem in the exhaust gas temperature sensor circuit in bank 1, which subsequently contains the number one...
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.