95 legacy automatic 140,XXX miles

Jalake · 05-07-2025, 10:20 AM

The car runs great for days at a time then all of a sudden it will stumble a couple of times and stall. some times it just stalls as if the key was shut off and no stumble. This always happens off throttle at idle.
Things I have checked.
compression 150 on all 4 cylinders.
fuel pressure 25 to 40 psi doesnt bleed down during the stall.
idle air control not causing the stall.
TPS and wiring checked and set correctly.
No vacuum leaks. 15 inhg at idle at 6500 feet above sea level.
igniter signal power ground good.

coil pack tests good and spark does not seem to drop off during the stumble/stall.
MAF replaced and didnt fix the stall. wiring checks good.
MAP sensor reads around 6 inhg at idle but koeo it reads 0.0 inhg?
Any ideas?

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Jalake · 05-07-2025, 10:29 AM

No codes no freeze frame data.

Elbert Bass · 05-13-2025, 07:01 PM

Have you measured fuel delivery volume? Have you monitored fuel pressure while driving? Have you considered water in the fuel? Have you replaced the fuel filter? Have you disconnected the filter and drained fuel from the inlet? Was it black?
Water will build up across the face of filter media and can block fuel flow. Once the flow is stopped fuel can flow again giving an intermittent stall/driveability issue. Many times it will start right back up.

Black 02 · 06-08-2025, 07:37 AM

Am having the same trouble, and just at idle, cold-ish engine. 2002 WRX, 170k. Have checked (and replaced ) all the bases original poster lists, plus new fuel pump and filter. Will try dry gas, to chase the water-theory.

Elbert Bass · 06-08-2025, 12:48 PM

Quote:

Originally Posted by Black 02

Am having the same trouble, and just at idle, cold-ish engine. 2002 WRX, 170k. Have checked (and replaced ) all the bases original poster lists, plus new fuel pump and filter. Will try dry gas, to chase the water-theory.

If you had enough water to cause this issue you should have seen a "puddle" below the gas in the tank when you swapped the pump. Water is heavier than gasoline and settle to the bottom of the tank.

I forgot this in my first response - replace the ignition switch electrical section. I have seen quite a few crack or become intermittent on the run contacts. Cold makes it worse for some reason...

arse_sidewards · 06-09-2025, 06:31 AM

Quote:

Originally Posted by Elbert Bass

If you had enough water to cause this issue you should have seen a "puddle" below the gas in the tank when you swapped the pump. Water is heavier than gasoline and settle to the bottom of the tank.

10% ethanol will allow a lot of water to be suspended in the gas.

05-07-2025, 10:20 AM	#1
Jalake Scooby Newbie Member#: 503650 Join Date: Jun 2019	95 legacy automatic 140,XXX miles The car runs great for days at a time then all of a sudden it will stumble a couple of times and stall. some times it just stalls as if the key was shut off and no stumble. This always happens off throttle at idle. Things I have checked. compression 150 on all 4 cylinders. fuel pressure 25 to 40 psi doesnt bleed down during the stall. idle air control not causing the stall. TPS and wiring checked and set correctly. No vacuum leaks. 15 inhg at idle at 6500 feet above sea level. igniter signal power ground good. coil pack tests good and spark does not seem to drop off during the stumble/stall. MAF replaced and didnt fix the stall. wiring checks good. MAP sensor reads around 6 inhg at idle but koeo it reads 0.0 inhg? Any ideas? * Registered users of the site do not see these ads.

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05-07-2025, 10:29 AM	#2
Jalake Scooby Newbie Member#: 503650 Join Date: Jun 2019	No codes no freeze frame data.

05-13-2025, 07:01 PM	#3
Elbert Bass Scooby Specialist Member#: 283429 Join Date: May 2011 Chapter/Region: South East Location: Down yonder. Vehicle: 2016 Crosstrek Silver	Have you measured fuel delivery volume? Have you monitored fuel pressure while driving? Have you considered water in the fuel? Have you replaced the fuel filter? Have you disconnected the filter and drained fuel from the inlet? Was it black? Water will build up across the face of filter media and can block fuel flow. Once the flow is stopped fuel can flow again giving an intermittent stall/driveability issue. Many times it will start right back up.

06-08-2025, 07:37 AM	#4
Black 02 Scooby Newbie Member#: 531163 Join Date: Aug 2022 Chapter/Region: NESIC Location: Southeastern Connecticut Vehicle: 2002 Impreza WRX Black	Am having the same trouble, and just at idle, cold-ish engine. 2002 WRX, 170k. Have checked (and replaced ) all the bases original poster lists, plus new fuel pump and filter. Will try dry gas, to chase the water-theory.