rough and hunting closed loop idle
Thread Starter
TECH Regular
Joined: Jan 2004
Posts: 496
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From: GARDEN GROVE, CA
rough and hunting closed loop idle This is what happens. In closed loop when I come to a stop at a signal and idle with be down a little and idle rough for a few secs then the idle will rev up and the idle won't be so rough. I drove the car for a week with the tps sensor unplugged and did't have this problem at all and the car had more power too. I thought maybe a bad plug connection so I soldered in a new harness and the problem is still there. I have tried another tps sensor and that didn't work. Does unplugging the tps put the car into open loop?
Thread Starter
TECH Regular
Joined: Jan 2004
Posts: 496
Likes: 0
From: GARDEN GROVE, CA
I have checked or replaced all the vacuum hoses for the pcv but will have to check others. As far as the 02 the short trims freeze and the the mv for the 02's drop from 3 digits to 2 digits when the idle drops. Starting with the first one on my predator then the second, third and fourth. I have tried new 02's and notta.
TECH Addict
Joined: Sep 2006
Posts: 2,591
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From: Massachusetts
Probably a vacuum leak but cleaning your TB, MAF and IAC could help.
Could also be MAF itself or O2 sensor or... really, lots of things. But check for a vacuum leak first.
You don't want to unplug TPS.
Could also be MAF itself or O2 sensor or... really, lots of things. But check for a vacuum leak first.
You don't want to unplug TPS.
TECH Apprentice
Joined: May 2006
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I had the same problem, idle would drop down to about 600 when I put the clutch in coming to a stop, then it would even back out at 900 after a few seconds. I just changed my nasty spark plugs and all is now good.
