sosullivan

Return the car immediately if you can. I had the exact same issue - it is loose guides on your timing chain. When you rev the engine, the slack is tightened up and the issue temporarily goes away. At idle, there is less tension on the chain and it begins to rattle. It will rapidly get worse with time and you will begin to hear the rattle at cold startup. The engine must be removed to replace the work timing chain tensioners as the timing chains (3 of them) are on the rear of the engine between the transmission. The parts are VERY expensive, as is the labor. Sorry to say, but you have just bought someone else's problem, my friend...

JayA64.2

Razor1981,
I am having the exact same problem with 05 A6 4.2. (Severe shaking and vibrations at idle, but then the car runs smooth without any noticeable issues. CLE flashing at idle but then just stays on while driving. Cylinder 5 & 6 misfires per the reader at o'rilleys. Replaced ignition coils on 5 & 6 but still same misfiring codes for 5 & 6.

Did you ever get your issues resolved?

Group members - Please share experience and a possible solution?

ianppk

Yes I have multiple vehicles that have done that your valve body is dirty seafoam or take the top half of the engine off clean the valve body with a toothbrush clean the throttle body with a toothbrush back up and running in no time

JayA64.2

I replaced all my spark plugs over the weekend,like and now just have randon miss fire code P0300.

Thanks for the reply.
Is sea foaming the best option/possible solution?

Also is it OK to use the Chevron techron or some other fuel system cleaners for the A6 4.2 vehicle?

Ryan Cart

[QUOTE=sosullivan;24564072]Any of you out there that own an Audi with a 4.2 engine should SELL IT AND RUN AWAY AS QUICKLY AS YOU CAN. BTW, I am not kidding.

These are DISPOSABLE engines that are lucky to make it to the 100K mark. If you don't believe me, do a search on Auto Trader for the highest mileage AUDI S4 with a 4.2 in the entire United States. You will not find one with more than ~110K.

The timing chain repair that is INEVITABLY REQUIRED on ALL these engines is $7300.00 at your local Audi dealer. Yeah, $7,300.00. Recommended "Maintenance" by Audi. 26 hours of labor at $150/hr, plus a few thousand dollars of overpriced plastic Audi parts.

In many cases, this is more than the vehicle is worth. I know. Been there, done that.

Error codes, misfires, rattling chains... These vehicles are overpriced, overrated, and unreliable. Audi should seriously be ashamed of putting such a poor product on the market. Get rid of this garbage Euro crap and buy a reliable C6 'Vette. Costs less to repair, and will eat any S4 for lunch.

Those who chose to ignore do so at the peril of their own bank account. You have been warned...[/QU

Doubleredrolex

My 4.2 in my 2004 S4 went to 302,000 before the chains went. Fixed that along with a bunch of other things while the engine was out. Car now has 326k and runs like new. Maintainance is key. If it hasn't been maintained then yes it will be dead at 100k. The 4.2 is not a disposable engine. It's a very reliable engine if properly maintained. And you would be crazy to have the audi dealer do your chains. You can get it done for half that price at a reputable independent audi/Mercedes repair shop.

Doubleredrolex

Sounds like the timing chains are about to fail. Stop driving the car immediately and take it to a good audi repair shop that's familiar with the 4.2 chains for advice. The car may not be worth repairing unless it's in very good shape with good compression. I realize this is an older thread but it's good info for someone else also. This is a common problem on this engine and this is most likely why the car was for sale. It's about a $5000+ repair and the engine needs to come out of the car. If they fail completely while the car is running, you will destroy your engine top end.

Doubleredrolex

Sorry I actually meant to quote Razor1981 but I do t have an option to delete or edit my post. Those bank 1 and 2 errors are usually related to timing. This other guys problem might be something easier.

Mahalo69

Doubleredrolex