1992 Subaru Legacy Car is sluggish when accelerating over 4

Tiny
RLADOUCEUR
  • MEMBER
  • 1992 SUBARU LEGACY
  • 4 CYL
  • AWD
  • MANUAL
  • 15,000 MILES
I have a subaru legacy. When I first start it up, before it gets warm, I can put the pedal to the floor and the car takes off with the turbo boosting how it should and providing a great feeling. However, once the car is running up to temp, usually within 5-10 minutes, when I put my foot down, around the 4000 RPM mark (Out of a 8000-8500 red line), it starts to buck. It will still accelerate, but not well. This only happens when it is warm. I suspect it's an O2 sensor or something like that, but am looking for advice.

Thanks!
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Sunday, September 5th, 2010 AT 9:19 PM

6 Replies

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 107,922 POSTS
Has the check engine light come on? Have you checked fuel pump pressure?
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Monday, September 6th, 2010 AT 12:15 AM
Tiny
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The check engine light has not come on. I also haven't checked the fuel pressure. I can get it to accelerate perfectly until it warms up. I assumed that indicated good fuel delivery. I was assuming more along the lines of the oxygen sensor or te MAF?
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Monday, September 6th, 2010 AT 12:21 AM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
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The O2 or any engine sensor should set the check engine light. I question if the fuel pump is weak and as it warms up, it can't keep up with the demand. Also, have you checked the catalytic converter is plugging?
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Monday, September 6th, 2010 AT 1:04 AM
Tiny
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I haven't checked the catalytic converter yet. I'm not quite sure how. Also, the fuel pump I can check, only, I am not entirely sure how.
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Monday, September 6th, 2010 AT 1:09 AM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
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Here is a how to for the fuel pump. It has both a video and directions. You will need a gauge, but most parts stores will lend or rent them.

https://www.2carpros.com/how_to/how_to_check_fuel_pressure.htm

As far as the cat, does it feel like a good bit of pressure is coming from the exhaust? After driving at night, check to see if it is glowing red hot.

Let me know what you find.

Joe
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Monday, September 6th, 2010 AT 8:07 PM
Tiny
STEVIE'S 42
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  • 7 POSTS
Try the knock (detection) sensor on bank 1 had a buddy doing the similar thing and because the knock sensor was failing or go bad caused the CPM to fail knock sensor also known has the crank sensor. If you call a auto store like AutoZone O'Reilly's auto etc.
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Monday, November 4th, 2019 AT 1:14 PM

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