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Discussion Starter #1
I bought the car used 3 years ago with 60,000km now at 172,000km. I drive a lot for work as I work in the automotive parts industry. Car was previously owned by a guy who lived in urban area so lots of short trips suspected. I have had a persistent shudder at idle for ages, I’ve routinely used a direct injection cleaner, that helped for a bit but the problem returned. I did all the usual, replaced plugs, coils, cleaned Maf sensor... but problem kept coming back. I had the pcv fail and oil consumption went up, I replaced it and oil consumption decreased, but misfire was worse, engine light started to come on, due to misfire, So I knew it was time to get a de carbon service. Took it to first shop, they “de carboned” the intake and installed 4 new Bosch injectors I supplied and the problem if anything was worse after the service. They performed a few diagnostic checks and said, “Your going to have to take it to the dealer”. Engine light came on consistently due to misfire.

I was pretty pissed, here’s a shop with a “reputation“ for being a good independent euro shop giving me the kiss off. So I took it to the shop I wanted too in the first place, even though they are 150km away from my house. I drove the car there and aside from poor idle, the car drove pretty “normally“ After my car passed all diagnostic checks, and aside from them saying my timing system sounds very noisy and may need service, the the misfire persisted, they started the top end tear down to see what was going on.

They found an exhaust rocker arm had popped off, lying in the head, luckily it didn’t get sucked into anything and cause further damage. The roller had a massive flat spot hammered into it, and the cam was damaged. The decarbon service I paid for at shop 1 was half assed, and the valves still had extensive tough carbon on the valves. the sealing edges of the valves had rough faces (non actually burnt), and the tech was very hesitant to reuse any. so all said and done, I have all new valves, rocker arms lifters, and all new timing components, (my 2011 had the original ”bad” timing chain tensioner.) I picked the car up yesterday and drove the 150km home, I have to take it easy on the new cam etc, but already the difference is huge. Car idles like it’s barely noticeable and even though I havent driven it hard I can tell it’s a lot more peppy. So aside from pistons And rings I have a fresh motor, no misfire, better fuel economy, and a happy A5 owner once again.
 

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What an excellent carbon clean eh???? Rip offs in the car industry are STILL common, even in these internet days, amazing!! Glad you sem to have a happy ending mate!
 

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I had this same problem and unfortunately went through the same “fault finding” processes. The garage said this was an unusual problem and seemed surprised to find it. Since the fix the car runs much better, engine is smooth and gets higher MPG.
 

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Discussion Starter #4
I had this same problem and unfortunately went through the same “fault finding” processes. The garage said this was an unusual problem and seemed surprised to find it. Since the fix the car runs much better, engine is smooth and gets higher MPG.
Yeah this shop was very surprised as well, they have a 20year VW/Audi master mechanic working there, and this was his first of this nature. I’m very happy with the repair, and I’ve noticed the increase in fuel economy as well. I’m going to do a short oil change this week to ensure there’s nothing left floating around after reassembly. I feel pretty good that this has been solved. I’m considering a water/methanol injection system purely to help keep the carbon buildup at bay. I have a friend with a Volvo V70r, who’s been running the system for over a year with nothing but good things to say.
 
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