Bad idle speeds

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thundercat

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My car is a Montana 2003. While engine temperature no reach normal level the driving is normal (idle > 700 rpm). But when temperature its about the normal, instead idle still at the usual 600 rpm the needle of revolutions fluctuates like if any time engine go turn off (usually happen when I driving and can't stop until reach my destiny), some minutes later idle revolutions ups more than 1500 rpm (without push the accelerator pedal), by sporadic appear 3 warnings (ABS, Service Traction System and air bag) for few seconds but they disappear when not touch the accelerator pedal (an electric issue?)
Never overheating, brakes works ok, codes are PO171 and PO300. I changed the IAC valve and the TPS sensor, but that doesn't fix. What could be happening? Thanks
 
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thundercat said:
My car is a Montana 2003. While engine temperature no reach normal level the driving is normal (idle > 700 rpm). But when temperature its about the normal, instead idle still at the usual 600 rpm the needle of revolutions fluctuates like if any time engine go turn off (usually happen when I driving and can't stop until reach my destiny), some minutes later idle revolutions ups more than 1500 rpm (without push the accelerator pedal), by sporadic appear 3 warnings (ABS, Service Traction System and air bag) for few seconds but they disappear when not touch the accelerator pedal (an electric issue?)
Never overheating, brakes works ok, codes are PO171 and PO300. I changed the IAC valve and the TPS sensor, but that doesn't fix. What could be happening? Thanks
Click to expand...
P0171 does not mention the parts you replaced.
Read this and follow the suggestions.
 
One of the rubber plugs at vacuum test ports of the intake manifold had disintegrated, that was the vacuum leak. Placed new ones in both. Fixed, thanks for your help (y)
 
Idle needle look stable but sometimes flashing: airbag, ABS and STS for few seconds and disappear then sporadic back again. Worried me may be an electrical problem that could worsen later. Any suggestions where to check? Thanks
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thundercat said:
Idle needle look stable but sometimes flashing: airbag, ABS and STS for few seconds and disappear then sporadic back again. Worried me may be an electrical problem that could worsen later. Any suggestions where to check? Thanks
Click to expand...
Does your scanner read codes in history for those other systems?
 
Scanner shows not codes stored in ECU. These 3 warnings appear sometimes while I push accelerator pedal. When I let to push they disappear some seconds later. They aren't permanently light on, but still look abnormal
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thundercat said:
Scanner shows not codes stored in ECU. These 3 warnings appear sometimes while I push accelerator pedal. When I let to push they disappear some seconds later. They aren't permanently light on, but still look abnormal
Click to expand...
I'm asking if you read the scanner manual to see if it reads abs and air bag codes?
 
Manual not say much, its a basic cheap one works bluetooth with phone app. I don't know if this detect ABS and airbag codes case they are. Never it light on the "service engine soon" signal
 
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