the_chancellor

Hi guys. New to the group and need your help.

I’m getting cylinder 4 misfire on my 2015 q5 2.0 tfsi. I have tried staggering the coils and the misfire did not move. I have replaced the spark plug and still getting the misfire. - P0304.

It’s especially bad when first starting the engine in the morning. Today was nearly -3 Celsius or about 30 Fahrenheit and when I started the engine it was shaking like crazy and misfiring. It gets ok when the car warms up. However if I cross more than 2500 rpm even in warm engine I get misfire and I have to stop the car. Turn the car of for a few mins and restarting it works fine.

Haven’t found any honest mechanic nearby to have a look. I was going to replace all coils and plugs today but I’m not optimistic and didn’t want to spend money on items that are not needed. Any suggestions? What else can I check myself.

Also does anyone know what this thing is on top of the engine (circled in red)? And any reasons why ignition coil will have this brown stuck on stuff? It’s rock solid. Appreciate all help. Thank you

silver_tt

Sounds like an injector since it's only one cylinder and you say it's bad when cold but issue goes away when the engine warms up.

For the hose you circled, it goes to the back/side of the intake manifold and there's an electrical solenoid it attaches to. Part numbers should be 06H-133-583-B

the_chancellor

Thank you @silver_tt

the hose has a paper-ish filter and it’s breaking off. Do you think this is related to misfire? Any thoughts on the brown residue on the ignition coils? Also I noticed oil seeping from top of the engine near the oil cap after misfires (even on top of engine cover). I’m guessing this is still pointing toward the injector? Any sure shot way to isolate and pin point that the injector is the culprit?

silver_tt

Yes that is somewhat common about that hose. You can verify the part number I gave and order a new one but it is not causing your issue.

For oil seeping there are some common points that leak on this engine due to aging rubber gaskets like the one on the plastic upper timing cover or possibly the one that goes on the oil cap.

Still probably an injector but maybe you can measure the fuel trims with a Audi specific scan tool like VCDS. You didn't say how many miles are on your engine but one of the biggest killers of injectors is gas quality; I personally only use Top Tier gas, 93 octane.

the_chancellor

Ok I will try vcds. I’m assuming it will give more info than the odb tool? It’s about 88k miles or about 138k km. I’ve always got 91 octane as per spec.

Will vcds indicate injector or something to that sort?

silver_tt

VCDS can do more than a standard OBD II tool which, if not Audi-specific, can even give incorrect error codes. VCDS is the best you can get but no matter what you choose be sure to use an Audi-specific reader.

VCDS will allow you to measure your fuel trims. Replacing injectors is not hard or expensive on this engine. If you believe it is the injector I highly recommend replacing the injector with a new OE one and not try to clean or fix the old one.

Mesquite77

+1 fuel injector, check this AZ post: https://www.audizine.com/forum/showt...le-white-smoke

the_chancellor

Thanks guys. It does look like the fuel injectors. I don't have access to VCDS and dont really want to go to the dealership. Audi Oakville in the GTA in Ontario, Canada, isn't very trustworthy. I considered driving to Kitchner as I have had positive experience at Audi KW, but the car doesn't handle anything over 2000 RPM well so I cannot take it on the highway. Every morning it starts rough and becomes ok after about 5-7 mins. Have to shut the engine off for a few mins if it gets too rough, but once warmed up it runs on if I drive gently. Cannot take on the highway even when warmed up as it doesn't take quick acceleration well.

Took to a mechanic out of the major city who said its likely the injectors or the intake runners, whatever that refers to. Car only has about 139K Km on it, but in the last year or two I have idled it a lot; at times couples hours or more to do office work in the car. But I have used 91 Octane at least 95% of the time, 5% being some pinch situations where I had to get whatever.

My question now is whether to keep the car after I get the injector done or not. It has had CV boots replaced very recently; which were fairly expensive from OEM, but thanks to Raxles I have rebuilt OEMs and not cheap china stuff that could fail next week. The coolant pump was replaced 6 months ago because of a leak; and in 6 months since the coolant level has come down again by about 1" below the min mark. So dont know what's going on there. I have had the car since new and I have driven Canada cost to coast from St. John's, NL, to Victoria, BC in it. I've also slept on the car for like a couple months while going though a rough patch with job situation a couple years ago. So I am kinda attached to it. But I dont want to keep a cash cow.

Thoughts?

DAIM

hi, I have exactly the same story with my Q5 2013, millage 230000 km, did you found what was the reason and fixed it?

Gabriel_k03

Hi buddy, had the same issue over here. At first i thought that i was having problems with the Mechatronic because under load (merging to highway) i could hear a clunky/ thud sound like banging from the central tunnel and was compleatly terrified. Went to the shop and did a full transmision maintanace ($640) and also went and got a tcu tune thinking that was the problem. 2 days later the same things stars happening again and took it to another shop and what happend was the the ignition cable harness was all toast becaus of the heat and what not and went ahead and replaced the whole ignition system. (NGK spark plugs, ECS injectors, Bosch R8 coil pack & wiring harness) and haven't had any issues what so ever.