wrx rough idle on stops or cold starts?

I have a 2015 wrx, recently its been boggling at stops and cold starts.

On a cold start the rpms are about 2k but once it drops it goes to about 200, it boggles and then jumps back up to 2k and repeats

On occasions it doesn't boggle on cold starts and it drives perfectly fine, then after about 5 minutes whenever I get to a stop rpms drop and it boggles and wants to die

I recently changed spark plugs about 500 miles ago(62,000 currently) 

Looking for a second opinion or advise on what to check

3 Answers

  • 2 months ago

    A hissing? Sounds like a vacuum leak. Loose hose, cracked intake boot..find the hissing and fix that.

  • 2 months ago

    Geo, this happened before the spark plug change, then q huge amount of misfires happened and couldn't accelerate, thought the root of the problems was spark plugs, it fixed for 3 weeks then it happened again thats why i made the post, there's also no hissing from the engine 

  • Barry
    Lv 5
    2 months ago

    Scan the fault codes. The ECU controls all throttle openings. Let's hope it's not that at fault. Maybe throttle body is faulty? You could try cleaning it and it's sensors with aerosol carb cleaner.

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