Rough idle
07-02-2018, 05:44 AM
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Rough idle
Hey all. I’m not sure if I’m posting in the right place however, I have a 2009 Audi A4 2.0t Quattro. It’s idling rough, I’ve taken it to two different places, one told me stretched timing chain and another told me it was electrical but couldn’t find the cause. It only idles hard until about 2,000 rpm. It also won’t start unless I’m tapping the gas pedal. Sometime the EPC will kick in and it won’t idle hard at all, but also the fan comes on no matter what it’s constantly running. I’m not sure what it is as I’ve been told tons of different things. The dealership quoted me $6,000 to fix it but the cars not worth much more than that so I’m hoping it’s just something that’s been missed.
07-02-2018, 06:47 AM
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BM, do you know how many miles are on the car? When were spark plugs last changed? What other issues with this car since you've owned it?
07-02-2018, 07:01 AM
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07-02-2018, 12:56 PM
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If you changed plugs and then the issue started, that's something to start with. But you would be better off with a scanner tool so you can see what codes the engine is throwing. If the issue is specific to a cylinder, then swap the coil and/or plug between that and another cylinder and see what the codes do. Do they stay with cylinder X, or move to the other cylinder. Make sure you reattached the MAF plug :-) I've forgotten that one a few times. Hopefully it didn't rest on the cat and half melt. :-D
Stretched chain, this is not a BMW N20. But it's a 2009. If you've never had the cam shaft chain tensioner replaced (the rev you need installed to be safe is latest, K rev), then you should be doing that ASAP. It can be easily checked via the inspection hole in the timing cover, well, relatively easily. There's a vid about it on youtube by shopdap (discussed in other threads too). Do note, if you do end up or have ended up with damage due to the tensioner, that's covered under a class action lawsuit. Though not sure if there's any mileage limits on the claims. The water pump runs off the back end of one of the balance shafts, but the balance shafts are on a different chain and tensioner than the cam shafts.
Rough idle with misfires codes could also point to the PCV. I've had the diaphragm tear on me twice, makes the car idle rough (runs fine at speed), but it sounds like a freight train whistle. If it's a vacuum related problem, pull the oil dipstick cap while idling. Does it smooth out?
I'd follow the codes and work what they point to. You could be trying all kinds of other people's solutions for the basic symptom and never solve your specific problem.
Stretched chain, this is not a BMW N20. But it's a 2009. If you've never had the cam shaft chain tensioner replaced (the rev you need installed to be safe is latest, K rev), then you should be doing that ASAP. It can be easily checked via the inspection hole in the timing cover, well, relatively easily. There's a vid about it on youtube by shopdap (discussed in other threads too). Do note, if you do end up or have ended up with damage due to the tensioner, that's covered under a class action lawsuit. Though not sure if there's any mileage limits on the claims. The water pump runs off the back end of one of the balance shafts, but the balance shafts are on a different chain and tensioner than the cam shafts.
Rough idle with misfires codes could also point to the PCV. I've had the diaphragm tear on me twice, makes the car idle rough (runs fine at speed), but it sounds like a freight train whistle. If it's a vacuum related problem, pull the oil dipstick cap while idling. Does it smooth out?
I'd follow the codes and work what they point to. You could be trying all kinds of other people's solutions for the basic symptom and never solve your specific problem.
07-03-2018, 06:05 AM
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The plugs and coil packs were changed after the problem started because the code reader showed it was misfiring on 1 and 4 so I changed Them all and still has the same problem.
07-10-2018, 07:30 AM
#6
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Ah, then you have to move past that idea and to what else could cause a misfire. Chain timing issues, PCV vacuum issues, etc. Only time I've had misfires is when the PCV messed up.
But could be you got a special and it has a chain condition issue. Did you confirm the tensioner is the K rev? If not, issues or not, you need to get that replaced ASAP. In which case, you might as well change the chain and guides while you're in there.
But could be you got a special and it has a chain condition issue. Did you confirm the tensioner is the K rev? If not, issues or not, you need to get that replaced ASAP. In which case, you might as well change the chain and guides while you're in there.
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