audiphobic

Started as intermittent flashing..turned out to be a cracked vacuum line. Cleared the codes - life was good again. Shortly afterwards, CEL came on and stayed on.

VAGed the vehicle and this is what I've done to try to get the CEL off.

Replaced plugs and ICP

Replaced three of four Oxygen sensors

Still shakes at idle and stutters when doing a constant speed of 60-65 mph.

DTC's: Multiple Cylinder Misfire and cylinder 6 misfire.

Bad spark plug - ICP???

Going to check cylinder 6 tomorrow..don't know what else to do.

Definitely open to suggestions. Thanks in advance.

4Driver4

Coolant temp sensor? O2's were a waste of money. They throw a different code.

audiphobic

VAG results stated that my O2 sensors were bad and needed replacing. How do you know when the coolant temp sensor needs replacing? Where is the coolant temp located? Would the coolant temp sensor have anything to do with the loss of coolant? My coolant sometimes purges itself..I'm guessing from the coolant tank but I could be wrong. Just want to narrow down all possibilities before I assume that it is my after-run pump. Where would the coolant lie when an after run pump goes bad? When I did my driver side front O2 sensor, I didn't see any coolant under the "Y" pipe. Thanks in advance.

GBW

Look at the tech article about the coolant afterrun pump. You'll see coolant residue on the top of the engine, probably on the passenger side.

<a href="https://www.audiworld.com/tech/eng69.shtml">check this out</a>

audiphobic

Turned out to be cylinder 6's spark plug had backed out a bit. The gap was totally off also. The alarming thing was that it had some oil on it..could be due to the spark plug not being tight (?) Cleaned it up, gapped the plug and reinstalled. Cleared the DTC and now I'm ready for my inspection. Thank you all for all the help.

4Driver4

Codes are clues that can be used to diagnose faulty parts. They are not absolutes.

4Driver4

Oil is from a leaky valve cover gasket.