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Old 03-29-2022, 01:55 AM   #1
sebastian323
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2006 WRX
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Default Hesitation when starting to accelerate, runs fine at full throttle

My naturally aspirated 2002 USDM Impreza hesitates under acceleration - unless I accelerate hard, then it responds well. I presume maybe it is having trouble under high load in closed loop, but handling open loop just fine ? Car is on a new long block, but has 344k miles on it so many sensors may be very old. What can I check for ? My first suspect is the oxygen sensor.
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Old 03-29-2022, 01:32 PM   #2
benflynn
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My first thought is fpr, is the vac line hooked up?
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Old 03-31-2022, 08:51 AM   #3
Mend22
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Quote:
Originally Posted by sebastian323 View Post
My first suspect is the oxygen sensor.
With 344k miles I’m guessing the CEL has been lit up for awhile. Have you pulled codes recently?

I agree with checking for a vacuum leak. Those hoses have lived a long life!
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Old 05-20-2022, 01:26 AM   #4
sebastian323
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Quote:
Originally Posted by benflynn View Post
My first thought is fpr, is the vac line hooked up?

It is connected.

Quote:
Originally Posted by Mend22 View Post
With 344k miles I'm guessing the CEL has been lit up for awhile. Have you pulled codes recently?

I agree with checking for a vacuum leak. Those hoses have lived a long life!
I only have codes for a catalyst fault. I will check for vacuum leaks

Last edited by sebastian323; 05-20-2022 at 01:36 AM.
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Old 05-26-2022, 01:23 AM   #5
Hypocrispy
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Check the valve clearance if you have a feeler gauge handy.
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