Rough Idle.
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1st Gear
Joined: Jan 2006
Posts: 48
From:
Rough Idle.
Have a CEL and slightly rough engine idle rpm, 2.8 30V Qattro. Ran the code reader and have the following codes:
1 B2 / S2 O2 sensor (passenger side aft of cat converter?) no reading
2 cylinders 1,2,3 misfire.
the sensor is an easy fix, I'll change the problematic one, not all of them.
as for the misfires, all 3 cylinders on one side of the engine? Seems uncanny, and Im ruling out coil packs as the culprit, since one side of each pack sends spark to 4,5,6 cylinders. will run a resistance check 1st chance i get.
The rough engine idle is only at idle, otherwise the engine does not hesistate, burp, etc during acceleration (light or heavy) and cruising speed. Am getting 26 mpg on the highway.
So Im down to spark plugs and cables, also injectors. Hopefully this will do the trick. Sticking with NGK OEM type.
Any input? TIA
1 B2 / S2 O2 sensor (passenger side aft of cat converter?) no reading
2 cylinders 1,2,3 misfire.
the sensor is an easy fix, I'll change the problematic one, not all of them.
as for the misfires, all 3 cylinders on one side of the engine? Seems uncanny, and Im ruling out coil packs as the culprit, since one side of each pack sends spark to 4,5,6 cylinders. will run a resistance check 1st chance i get.
The rough engine idle is only at idle, otherwise the engine does not hesistate, burp, etc during acceleration (light or heavy) and cruising speed. Am getting 26 mpg on the highway.
So Im down to spark plugs and cables, also injectors. Hopefully this will do the trick. Sticking with NGK OEM type.
Any input? TIA
Thread Starter
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1st Gear
Joined: Jan 2006
Posts: 48
From:
RE: Rough Idle.
follow up...
changed the plugs and O2 sensor. still have the rough idle. found some dried up vacuum hoses and replaced, maybe need to do the rest of them to be rest assured.
i run 93 octane, have searched the forums and found that running a lower grade has helped with ridding the misfires. will try this out as ASAP and see what happens.
overall, i am perplexed.
BTW, is it possible to clear the check engine light without any special tools?
changed the plugs and O2 sensor. still have the rough idle. found some dried up vacuum hoses and replaced, maybe need to do the rest of them to be rest assured.
i run 93 octane, have searched the forums and found that running a lower grade has helped with ridding the misfires. will try this out as ASAP and see what happens.
overall, i am perplexed.
BTW, is it possible to clear the check engine light without any special tools?
Joined: Nov 2005
Posts: 12,826
From:
RE: Rough Idle.
well going back to the old days and no codes the first place to start is the throttle body and clean it out the second is the idle air bypass/idle control valve but on the newer cars the code is the breaker of the problem
Thread Starter
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1st Gear
Joined: Jan 2006
Posts: 48
From:
RE: Rough Idle.
P0160 O2 sensor ckt no activity detected (bank 2 sensor 2) - replaced this, hopefully code will not show at next diagnostic
P0300 random multiple cyl misfire
P0301 cyl 1 misfire
P0302 cyl 2 misfire
P0303 cyl 3 misfire
as i mentioned in my original post, i thought it was unusual that cyl's 1,2,3 (all on the same side) misfire. who knows.
installed OEM NGK plugs, the previous plugs didnt look bad at all, but I don't know how long they've been in there for - changed them on principle. running out of thoughts here.
P0300 random multiple cyl misfire
P0301 cyl 1 misfire
P0302 cyl 2 misfire
P0303 cyl 3 misfire
as i mentioned in my original post, i thought it was unusual that cyl's 1,2,3 (all on the same side) misfire. who knows.
installed OEM NGK plugs, the previous plugs didnt look bad at all, but I don't know how long they've been in there for - changed them on principle. running out of thoughts here.