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04-25-2022, 06:06 PM | #1 |
Scooby Newbie
Member#: 511233
Join Date: Jan 2020
Location: Nashville, TN
Vehicle:2003 WRX Gun metal grey |
Stutter/Stall Issue. I'm lost!
Well for the past 6-7 weeks i've had this weird issue where from a stand still my car will occasionally sputter (acts like a misfire) and either stall or correct itself, nothing i do with the throttle seems to help when it stalls, when it doesn't sometimes i can give it more juice and it'll go along just fine. Lately the issue has become more frequent (probably due to more stop and go traffic in downtown nashville) and occasionally when I'm downshifting i'll go to give it a rev match blip and it'll do nothing. The car idles perfectly fine staying right at 14.70 AFR with 0-1% correction consistently. I have tried to replicate it but it just seems to be completely random. I'll have days where it doesn't do it all and then days like yesterday where it stalled 4 times in an hour.
Things i've done so far: 1. cleaned MAF sensor, replaced MAF sensor 2. smoke tested for vacuum leaks (none) 3. Changed plugs and tried a friends coils 4. compression and leak down test (both passed with flying colors for 200k miles) 5. Cleaned the IACV (yes i replaced the gasket) I'm sure I've tried other things but i can't account for the endless hours staring under the hood wanting to pull my hair out. Any help is greatly appreciated and i did grab a couple logs (probably the wrong info) to see if it would help.
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Last edited by Boostedidiot; 04-25-2022 at 06:18 PM. |
04-26-2022, 07:41 AM | #2 |
Scooby Newbie
Member#: 23128
Join Date: Aug 2002
Location: Long Island
Vehicle:2003 WRX Sedan Sonic Yellow |
What about testing/replacing crank/cam sensors?
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04-26-2022, 08:46 AM | #3 |
Scooby Specialist
Member#: 283429
Join Date: May 2011
Chapter/Region:
South East
Location: Down yonder.
Vehicle:2016 Fuji Sunfire 03 Silver |
Have you watched your TPS value as you slowly open the throttle?
I have seen TPS sensors get a "bad" spot in the carbon film and give intermittent values just off throttle. Value should be 0.2 volts to 1.0 volts closed and then increase smoothly with no erratic readings to 4.2 volts to 4.7 volts WOT. You can also measure resistance across the sensor as you slowly open throttle or measure the output voltage. Another thing would be check for voltage drop across the sensor ground - poor ground will cause the sensor to read erratic. |
04-27-2022, 01:33 AM | #4 |
Scooby Newbie
Member#: 511233
Join Date: Jan 2020
Location: Nashville, TN
Vehicle:2003 WRX Gun metal grey |
I'm going to test them in the morning, today i went over all my grounds and cleaned them up. Was going to replace them to see if it made a difference but currently can't afford 110 bucks for 2 cam sensors and 30 bucks for the crank sensor lol
Last edited by Boostedidiot; 04-27-2022 at 07:12 PM. |
04-27-2022, 01:34 AM | #5 | |
Scooby Newbie
Member#: 511233
Join Date: Jan 2020
Location: Nashville, TN
Vehicle:2003 WRX Gun metal grey |
Quote:
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04-27-2022, 09:03 AM | #6 |
Scooby Specialist
Member#: 283429
Join Date: May 2011
Chapter/Region:
South East
Location: Down yonder.
Vehicle:2016 Fuji Sunfire 03 Silver |
Yes - those are KOEO tests - Key On Engine Off. Actually the ground I was referring to in my response is the TPS sensor ground which goes back to the ECM. Do you have a scan tool that reads live ECM data? That will show you the TPS value as you open/close throttle.
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04-27-2022, 06:30 PM | #7 | |
Scooby Newbie
Member#: 511233
Join Date: Jan 2020
Location: Nashville, TN
Vehicle:2003 WRX Gun metal grey |
Quote:
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04-27-2022, 08:58 PM | #8 |
Scooby Specialist
Member#: 283429
Join Date: May 2011
Chapter/Region:
South East
Location: Down yonder.
Vehicle:2016 Fuji Sunfire 03 Silver |
Hey, one thing I forgot - and that reading made me think of it - is there a little bit of slack in the throttle cable at the throttle body? There should be. If the cable is tight it can hold the throttle open a very small amount. If you adjust the TPS that way you will have the range out of whack and can cause bucking.
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04-27-2022, 09:36 PM | #9 | |
Scooby Newbie
Member#: 511233
Join Date: Jan 2020
Location: Nashville, TN
Vehicle:2003 WRX Gun metal grey |
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05-01-2022, 04:44 PM | #10 |
Scooby Newbie
Member#: 525779
Join Date: Jul 2021
Location: SLC, UT
Vehicle:2003 WRX Silver |
My car has kind of always done a similar thing. Every now and then after a cold start, my car just sputters and dies like it is losing fuel pressure for a second. After the car dies you can start it up and it runs great the rest of the drive. Just to clarify, This happens randomly. And sometimes you can start driving and the car starts to sputter, when this happens you can floor the car but it doesn't do anything. It just seems to prolong the inevitable. But recently I have found a solution, I can keep the car in gear (while rolling) without pushing the clutch and just turn the key to the off position and then on. It seems like the car just resets itself and is fine for the rest of the drive. I am not really sure where to check first. It kind of sounds like an ECU issue.
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05-04-2022, 08:09 PM | #11 | |
Scooby Newbie
Member#: 511233
Join Date: Jan 2020
Location: Nashville, TN
Vehicle:2003 WRX Gun metal grey |
Quote:
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05-04-2022, 10:13 PM | #12 | |
Scooby Newbie
Member#: 525779
Join Date: Jul 2021
Location: SLC, UT
Vehicle:2003 WRX Silver |
Quote:
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05-06-2022, 11:28 AM | #13 |
Scooby Newbie
Member#: 511233
Join Date: Jan 2020
Location: Nashville, TN
Vehicle:2003 WRX Gun metal grey |
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05-06-2022, 11:47 AM | #14 |
Scooby Specialist
Member#: 459692
Join Date: Dec 2016
Chapter/Region:
South East
Location: Hampton Roads Va
Vehicle:2019 WRX STI silica black |
He may of been referring to disconnecting the battery and holding the brake pedal down for a few seconds. You will retain your tune.
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05-06-2022, 03:39 PM | #15 |
Scooby Newbie
Member#: 525779
Join Date: Jul 2021
Location: SLC, UT
Vehicle:2003 WRX Silver |
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05-11-2022, 10:30 AM | #16 |
Scooby Newbie
Member#: 511233
Join Date: Jan 2020
Location: Nashville, TN
Vehicle:2003 WRX Gun metal grey |
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05-11-2022, 11:49 AM | #17 |
Scooby Newbie
Member#: 525779
Join Date: Jul 2021
Location: SLC, UT
Vehicle:2003 WRX Silver |
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05-11-2022, 09:41 PM | #18 |
Scooby Newbie
Member#: 511233
Join Date: Jan 2020
Location: Nashville, TN
Vehicle:2003 WRX Gun metal grey |
Well i made some progress today. I noticed it was idling a little weird right before it stuttered and inevitably stalled so i stopped a friends house that was close and started touching clips and grounds while it was running and behold the connection to the coil pack on cylinder 2 is in some way shape or form messed up, i can't recreate it perfectly but playing with it causes the same rough idle into a stall
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05-11-2022, 10:09 PM | #19 | |
Scooby Newbie
Member#: 525779
Join Date: Jul 2021
Location: SLC, UT
Vehicle:2003 WRX Silver |
Quote:
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05-11-2022, 10:12 PM | #20 | |
Scooby Newbie
Member#: 525779
Join Date: Jul 2021
Location: SLC, UT
Vehicle:2003 WRX Silver |
Quote:
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05-11-2022, 10:14 PM | #21 |
Scooby Newbie
Member#: 525779
Join Date: Jul 2021
Location: SLC, UT
Vehicle:2003 WRX Silver |
didn't mean to post twice
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05-16-2022, 07:37 PM | #22 | |
Scooby Specialist
Member#: 333468
Join Date: Sep 2012
Chapter/Region:
RMIC
Location: SLC, UT
Vehicle:93 SS - 06 OB XT 03 WRB GD 205/22T 20G-XT |
Quote:
I had a stalling/stuttering issue and it turned out it was the coilpack(s). NGK coil packs from RockAuto are great. They run about $62 each. I would advise against getting cheap ones. Things I checked/replaced before the coil packs: Checked ECU for stored codes Reset ECU multiple times Ran new ground lines Checked fuel pump and fuel pump sock (there have been instances where the sock gets so clogged up it causes fueling issues) Replaced fuel filter Replaced fuel pressure regulator Checked for boost leaks (found a loose intake coupler) Replaced MAF with a new spare I had laying around Replaced Spark Plugs. Replaced alternator with new higher output voltage unit (had it laying around) Logged during pulls - no knock detected. I had no misfire codes which also made the problem hard to track down. After I replaced all four coil packs the car was pulling like it used to. Replacing the coil packs was last on my list of things to do, so it was a frustrating process. When I replaced the coils I wasn't even sure if it was going to help so I didn't bother and try to isolate which coil(s) were causing the problem. Do yourself a favor and just replace all four. Last edited by monkeyposeur; 05-16-2022 at 07:44 PM. |
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05-20-2022, 01:20 AM | #23 | |
Scooby Newbie
Member#: 511233
Join Date: Jan 2020
Location: Nashville, TN
Vehicle:2003 WRX Gun metal grey |
Quote:
I've now replaced all 4 coils and plugs with replacements from subaru (get a discount wife works there). Replaced fuel filter today to see if that was an issue. Still just getting nowhere. I did notice i'm running very very lean so i think it'll be going to the shop for a new tune. Not sure what changed but i'm tired of throwing money at things that clearly aren't helping. |
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05-20-2022, 06:09 AM | #24 |
Scooby Specialist
Member#: 459692
Join Date: Dec 2016
Chapter/Region:
South East
Location: Hampton Roads Va
Vehicle:2019 WRX STI silica black |
iWire sells the replacement plug for your coil packs. They're cheap and worth a try at this point.
Last edited by undyjr; 05-20-2022 at 06:10 AM. Reason: it's early... |
12-07-2022, 07:26 PM | #25 |
Scooby Specialist
Member#: 333468
Join Date: Sep 2012
Chapter/Region:
RMIC
Location: SLC, UT
Vehicle:93 SS - 06 OB XT 03 WRB GD 205/22T 20G-XT |
Oops, double posted somehow.
Last edited by monkeyposeur; 12-08-2022 at 02:13 PM. |
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