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Bad Idle Symptoms and odd behavior

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  • Bad Idle Symptoms and odd behavior

    So i need some help here guys - heres the back story.

    So its a b18a1 , OBD0.
    Just started driving car this summer but the brakes were extremely hard to press and brake but car seemed to run ok with the idle just but couldnt slam on the brakes.

    Come to find out the one way valve to the brake booster was reversed. I then fixed that and drove the car again and the brakes had been locking up , long story short i had the wrong master cylinder on and it was constantly depressing brakes so i fixed that.

    I thought awesome! lets get on the road. Started driving and then when i went to brake from 50 approaching a light the car died when i got to 0-5 MPH, if i baby the throttle i can get it to stay on but mostly just dies but can start it right back up.

    So last night i let the car warm up and it idles somewhat normal but every 5 seconds or so you hear a quick hiccup like a small misfire or burp in the idle. So i shut car off and re-clean IACV and FITV. Check for hose leaks etc..

    So then i did relearn the idle according to factory, and then reset my ecu. After resetting ECU now the idle bounces from 250 RPM - 1000 RPM , and if i hit the brakes and hold the brake and clutch in the Idle bounces up to 1500 and then just drops to like 200 and then goes back to the noraml idle bounce.

    Not sure what im missing but it seems odd that the idle sstarted bouncing after a reset of idle and ECU.

    I do have new plugs wires and O2 sensor coming and i already have massive grounds going to everything.

    What am i missing?

  • #2
    oh and if i unplug the IACV while the car is running the bouncing idle goes away, even though like i said it didnt bounce before hand so its has me questioning if it just didnt learn the idle correclty or could the IACV be bad or is it something else.


    • #3
      Maybe there's a vacuum leak at the brake booster? Sounds like the whole master-cylinder/BB installation is, or has been super funky & chunky. I replaced one once, but it's been a while, I don't remember it being too bad though. Do you have a shop manual, or at least a Hayne's (the better one IMO at O'Really's etc,..)?