Few questions for you professionals - I'm at my wits end.

Ok, first... its a B6 2005 Audi A4 3.0 Quattro 5-speed Tiptronic Transmission - roughly 66,000 miles. Purchased it this March... since then I've done the timing belt, serp tensioner, water pump, plugs, 4 rotors, 4 pads, oil change (0w40 mobil 1), fuel filter, model specific K&N intake filter (oem box), coolant, brake fluid, transmission fluid/filter/gaskets, front and rear diff gear oil, rear main seal... and I think that's about it.

Absolutely zero fault codes. None.

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Anyway I'm having a few issues and hope you can steer me in the right direction.

1.) When decelerating at low speed (i.e. let off the gas in a parking lot or drive through) the engine sounds like a diesel. tick tick tick tick tick tick. When I give it gas, the tick goes faster until about 1500-2000rpm and then it goes away. When I slow down, the tick comes back and slows with the RPM.

2.) When the car is in park, once it warms up and the RPM goes back down to "normal", the car shakes. Not like an earthquake, but certainly not smooth and very noticeable vs when parked in drive (at a stop light for example). Once I put it in any gear (R, D, TIP, S) it goes away. Granted, in "gear" the idle rpm is higher, but this seems strange.

3.) I just noticed recently (now that it's colder out) that I can hear a hiss/whistle sound from the center/right of the front of my car anytime I accelerate. Most pronounced around 2800-3000RPM, but if I let off, on, off, on it will still do it. Sounds like a turbo or quiet blow off valve almost, and my N/A V6 does not have either. My PCV was just delivered today, going to give that a shot. I didn't order hoses though, so if it's a leak then I'll have to get them. Hoping I can snake it under the intake manifold without removing 1/2 the engine.

4.) Most noticeable after parking, when I go from park to drive, or park/reverse/drive and take off (go forward) the front of my car makes a CLUNK sound - I can feel it in the pedals. Once I'm moving, it doesn't happen again. Was thinking it may be the brake pads, or control arms... but the pads don't show any wear from sliding around (at least externally - haven't taken them apart), and I'm not sure how to test the control arms without just replacing them.

Any ideas, tips, etc. would be greatly appreciated.

Thank you so much!!!

 

Got a video last night of the whistle. 3-4 seconds in. https://youtu.be/igCC7MNvv9w

 

Here's the clunk around 1-2 seconds in

https://youtu.be/DTEPGp6XiPo

 

Pcv dramatically improved idle. Honestly it's probably fixed. However... when I take the oil cap off (which I can still do fairly easily) there is still a good amount of suction. If I cover it with my hand it certainly has suction.

How much is too much? Is there a minimum? Or do I have a leak in a hose somewhere?

Thanks!

 

Local Indy shop found a leak between the throttle body and the engine. Going to have them replace the gasket, clean the throttle body a bit, and replace the vacuum lines with new 3.5mm lines while they're there. Hopefully that explains the poor performance and the diesel sound. If it doesn't - I guess the chain tensioner is next on the list. Sigh...

Thanks everyone!

 

Sorry for the "spam" so late into your problem. Figured since you had so many responses I'll add some ideas to it . I don't have this model but overall Audi's are the same (mostly).

The ticking sound is usually lifters. The v8 in that year range was notorious for lifter issues/noise so I would think the v6 might have the same problem. I think the design was not perfect and they didn't get enough lubrication on cold starts and therefore you will hear a ticking noise until higher rpm when the oil pressure increased to deliver enough slickness. Either way I would recommend to open up the valve cover, and get your hands dirty if you want to get rid of the noise. On my old v8 (2002) I simply lived with it and over the 8 years I had it - it never gotten worse.
I would also recommend to look at the cam while you have everything open - they are known to wear down as well and creating a ticking sound.

The hissing sound you described in conjunction with shaking/rough idle definitely sounds like vacuum issue. Either PCV related or the lines itself. Since you are already on-top of that I guess no further comments needed

Last thing on your list was a clunk sound after the car has been parked and you put it into drive. If it does make the sound while your foot remains on the brakes - transmission related. If it only makes the sound when you let go of the brakes - check the brake pads/rotors again and see if they didn't bed in properly.

 

Thanks for the info everyone! And for the corrections - my first german car so obviously I need to be more precise in my verbiage vs my chevrolet LOL.

Took it to the indy shop and they did a VAG scan - the throttle body adaptation will not work. The error code (which I didn't think to ask for since they are friends of mine) will not clear. He said most likely the throttle body is dirty and needs to be cleaned, new o-rings, and then do the adaptation. I also picked up the breather hose for under the intake manifold since he'll be right there anyway. Also got new vacuum lines, new check valves, and a few misc clips that I noticed were replaced with zip ties by the PO. Hopefully that does it.

With that said, question... would a dirty unadjusted throttle body make the diesel sound at low rpm when on and off the gas in a parking lot? I'd imagine it's dumping fuel to overcompensate for how lean it is and essentially stalling the engine which is restarted by me moving in gear. Sounds plausible - and would be WAY better than lifters/cams/etc.

I'm waiting on parts, should get them in and get the job done early next week. Will keep you posted.

 

Thank you for the info! I'll look into that.

 

Couple more videos if this helps too.

Clunk:
Diesel sound:

 

I listened to the "clunk" video 3 times and could not hear it

The diesel sound however is really more of a diesel sound vs ticking sound. Maybe if you get closer a ticking would be more audible. I'm not convinced the Throttle body has anything to do with that sound. I'm still steering towards Cams or the parts around it (chain, tensioner, lobe). There was a report of someone having the same sound and it was cured by replacing the timing belt tensioner that was failing. So that gives you plenty of things to check and replace should you have not touched any of those parts yet.

If there is a ticking sound when you get closer I would also look at the hydraulic lifters.

As to your TB - with some luck you can clean it and run the adjustment afterwards. However the is a chance you might have to replace it (again unlikely related to the rattling sound - more of a performance issue).