Low/rough idle sitting at a light (worse with AC on)
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Low/rough idle sitting at a light (worse with AC on)
I've read nearly all of the rough idle posts pertaining to my year 4runner and similar year Tacoma. All to conclude that no one really knows the cause. The motor was just swapped over (just the block) did end up needing a new knock sensor wire but feel that's unrelated. My question is what electrical component controls the idle? I hate to shoot in the dark and just start replacing crap if um
unecesary, yes the motor is elec. Components are older 245k ish (what hasn't already been replaced). Anyone actually fix this rough idle? The last code I got was for the front o2 sensor (replaced 12/9) and a missfire on cyl 1&5 (a coil pack perhaps?). Help as always will be greatly appreciated.
A
unecesary, yes the motor is elec. Components are older 245k ish (what hasn't already been replaced). Anyone actually fix this rough idle? The last code I got was for the front o2 sensor (replaced 12/9) and a missfire on cyl 1&5 (a coil pack perhaps?). Help as always will be greatly appreciated.
A
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Not sure on the 3.4L, but I do know that the IAC (Idle Air Control Valve) can be the culprit for Chevy's with the problem you are describing. Are you sure its cleaned and functioning properly? It controls idle electronically. It also could be dead if the AC is causing a higher load and not adjusting idle correctly...
A misfire on two adjoining cylinders would say a coil pack... but 1 and 5 wouldn't make much sense...
A misfire on two adjoining cylinders would say a coil pack... but 1 and 5 wouldn't make much sense...
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First thing to keep in mind is you are posting at 9:30 and 11:00am on a work day - it may be tonight before a lot of people are able to come on the board and post.
Just to keep that in perspective.
Have you done a full tune-up recently? Clean the MAF? TB? Replace plugs? How long as it been having the problem? Tried higher octane fuel? Etc...
Fink
Just to keep that in perspective.
Have you done a full tune-up recently? Clean the MAF? TB? Replace plugs? How long as it been having the problem? Tried higher octane fuel? Etc...
Fink
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I have a front O2 to swap in but waiting because they cannot be returned, I spritzed the MAF but should look at throttle body.
Recent motor swap has left me with a rough idle, it was just the block that was swapped (of course).
Air filter cleaned and lightly oiled every 30k
Fuel filter 20k
Plugs OE 20K
Wires OE 20K
Front O2 Dec of 2009 likely 20k
Rear O2 controlled by simulator
Knock sensor 245K
Knock sensor wiring OE NEW
MAF 245K
PCV within the last year
EGR NFK? No freakin clue if replaced or exists
Have checked and rechecked vac. hoses and found one with a crack but not near where the hose inserts, (the tube inserts well past the cracked hose portion).
What else is there?
A
Recent motor swap has left me with a rough idle, it was just the block that was swapped (of course).
Air filter cleaned and lightly oiled every 30k
Fuel filter 20k
Plugs OE 20K
Wires OE 20K
Front O2 Dec of 2009 likely 20k
Rear O2 controlled by simulator
Knock sensor 245K
Knock sensor wiring OE NEW
MAF 245K
PCV within the last year
EGR NFK? No freakin clue if replaced or exists
Have checked and rechecked vac. hoses and found one with a crack but not near where the hose inserts, (the tube inserts well past the cracked hose portion).
What else is there?
A
Last edited by xcmountain80; 06-15-2010 at 09:08 AM.
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I have a front O2 to swap in but waiting because they cannot be returned, I spritzed the MAF but should look at throttle body.
Recent motor swap has left me with a rough idle, it was just the block that was swapped (of course).
Plugs OE 20K
Wires OE 20K
Front O2 Dec of 2009 likely 20k
Rear O2 controlled by simulator
Knock sensor 245K
Knock sensor wiring OE NEW
MAF 245K
PCV within the last year
EGR NFK? No freakin clue if replaced or exists
Have checked and rechecked vac. hoses and found one with a crack but not near where the hose inserts, (the tube inserts well past the cracked hose portion).
What else is there?
A
Recent motor swap has left me with a rough idle, it was just the block that was swapped (of course).
Plugs OE 20K
Wires OE 20K
Front O2 Dec of 2009 likely 20k
Rear O2 controlled by simulator
Knock sensor 245K
Knock sensor wiring OE NEW
MAF 245K
PCV within the last year
EGR NFK? No freakin clue if replaced or exists
Have checked and rechecked vac. hoses and found one with a crack but not near where the hose inserts, (the tube inserts well past the cracked hose portion).
What else is there?
A
Have you replaced the fuel filter?
Fink
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Mine was doing this a couple days ago. The RPM's would drop down to about 400-500 @ stop lights, and if I turned the A/C on at a light it would surge up and down, up and down. This thread and this thread helped me the most. Pull apart your IAC and you'll see it will be all gummed up with black stuff. Clean it out with brake cleaner. You may need to wiggle the plate around to get everything. I didn't need to pull the sensor off, just the 4 screws that hold the part to the intake. Worked for me, idling smoothly again . All in all, 45 min. job taking your time.
I will be doing this to any 3.4L I get in the future during my cleaning regimen.
I will be doing this to any 3.4L I get in the future during my cleaning regimen.
Last edited by CYi5; 06-15-2010 at 10:00 AM.
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