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Discussion Starter · #1 ·
Hey everyone, thanks for reading. Here's my situation: On cold start engine will rev up and idle fine, give it any gas and it will stutter and not gain any rpm. Let off the gas and it idles fine again. After it warms up for a few minutes it drives fine. No CEL.

Here's what I've replaced so far
- Intake Manifold Gaskets
- MAP sensor
- Throttle body (including IAC)
- Coil, Plugs, Wires
- Injectors
- O2 sensor
- Main Relay
- Coolant Temp Sensor
- Throttle Position Sensor

Holds Vacuum. No CEL. I've fired the parts cannon at this thing and nothing seems to help. Any ideas?
 

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2019 Forester Sport CVT
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316 Posts
Hey everyone, thanks for reading. Here's my situation: On cold start engine will rev up and idle fine, give it any gas and it will stutter and not gain any rpm. Let off the gas and it idles fine again. After it warms up for a few minutes it drives fine. No CEL.

Here's what I've replaced so far
- Intake Manifold Gaskets
- MAP sensor
- Throttle body (including IAC)
- Coil, Plugs, Wires
- Injectors
- O2 sensor
- Main Relay
- Coolant Temp Sensor
- Throttle Position Sensor

Holds Vacuum. No CEL. I've fired the parts cannon at this thing and nothing seems to help. Any ideas?
Include your Year, Model & Miles so readers can better assist you.
 

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2013 crosstrek, Forester+
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150 Posts
Although I am no expert on the 2005 model, my earlier ones have two coolant temp devices: a sender for the dash and a sensor for the ECU. Is it possible you replaced the dash sender rather than the ECU sensor? From the amount of parts you have replaced I guess this is unlikely--just a thought. Also, would a real time scan tool perhaps reveal anything? And finally, if you are in a really cold climate perhaps warming it up a little is not a bad thing.
 

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Discussion Starter · #5 ·
Although I am no expert on the 2005 model, my earlier ones have two coolant temp devices: a sender for the dash and a sensor for the ECU. Is it possible you replaced the dash sender rather than the ECU sensor? From the amount of parts you have replaced I guess this is unlikely--just a thought. Also, would a real time scan tool perhaps reveal anything? And finally, if you are in a really cold climate perhaps warming it up a little is not a bad thing.

On these newer models they went to a single coolant temperature sensor but I did consider that possibility. I am thinking about taking it to a shop and having a diagnostic done with their fancy scan tool. And yes its does get cold here but my 98 legacy starts up no problem, something is definitely fishy.

Here are my two lines of thinking at the moment. The O2 sensor has a heater that may not be getting voltage causing the A/F to be off until it warms with the engine. Will break out the volt meter tonight. It may also have gotten a tank of bad gas. Once the engine warms up the gas ignites more consistently?

Any other input is welcome!
 

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Discussion Starter · #6 ·
SOLVED!

The gas in the tank had gone bad. There was about an eighth left, put a few gallons of ethanol free in with some fuel additive and immediately noticed a difference. Should have known better since the car had been sitting around for 6 plus months. Still stutters a bit when cold but I believe its because its working out the old gas. Hope this helps anyone running into this problem.
 
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