Bryans12v

Ive been having a real hard time with this car lately. I inherited another 12v in a 97 A4Q body. It had a misfire along the 4,5,6 bank for about 3000 miles or so, intermittent and not to noticable. Someone had done the timing belt without the proper tools and had it a tooth off on both cams.

Got that fixed after two tries.

The car had a massive exhaust leak at both flex's and wanted to wait till I got her purring before I sent her off to get it quiet. Changed all the fluids, output flange seals, gear oils, etc..

500 miles later, purring with NO misses or CEL (no pending faults either) and I got the car inspected legitimately for the first time in 5 years. *phew*!

I take it in to get the new flex's welded in. Sounds great but as soon as I left the parking lot I noticed some stumbling going into second gear. As I got it in the garage, it would barely run. Let it idle, scoped around and couldnt hear much. CEL comes on with a misfire on Cyl 6. I pulled the plug, Sauturated in oil. All others looked clean and uniform. I checked compression and couldnt get any reading on cyl 3 and 6. 3 looked like it wanted to bump up but didnt, even after 30secs of cranking. 6 didnt budge at ALL!

I started pulling it apart to find the PCV system was sludgelocked, completely. Still this doesnt explain why I have no compression on 6.

I pulled the heads. I had to. As I pulled the valve cover (leaking anyway) I discovered we had a bad sludge problem and I have to excavate. I was hoping for a bad head gasket but it looked fine! The piston looks fine with no holes or cracks, walls look good and now Im scratching my head wondering if it needs rings.

I just cant see it being rings being that it happened so suddenly. Its not the injectors. I ohm'd them and swapped and stayed on on 6. Coil, wires, plugs- all OEM less than 1000 miles on them.

Only code I had was a mis on 6. The car felt like it was cammed to hell and would barely hold an idle.

Anyone have any ideas before I go ripping the bottom end off this thing. I really dont have the money to spend on a crazy rebuild with HP parts. I just want a normal, slow, sexy 12v A4 running again.

Prospeeder

That would be a burnt valve. and yes it happens for no reason very suddenly. Can happen to any engine. pull the head it will be painfully obvious.