CAT light flashing / misfire

[ricointheuk]

Hi

I have a A8 4.2Q 1996. On a recent journey the CAT light began flashing and the engine began to misfire.

I have VAG codes for: cylinder 3 misfire, multiple cylinder misfires. I have already changed the spark plugs and 2 pre cat o2 sensors and the coil pack on cylinder 3.

While changing the o2 sensors I noticed that the air intake boot that connects directly to the engine had split. I changed this as well. All breather pipes are intact, although could do with replacing.

No change to the problems from doing the above.

Any ideas of what to do / try / test next?

Thanks Richard

[ricointheuk]

Originally Posted by ricointheuk

Hi

I have a A8 4.2Q 1996. On a recent journey the CAT light began flashing and the engine began to misfire.

I have VAG codes for: cylinder 3 misfire, multiple cylinder misfires. I have already changed the spark plugs and 2 pre cat o2 sensors and the coil pack on cylinder 3.

While changing the o2 sensors I noticed that the air intake boot that connects directly to the engine had split. I changed this as well. All breather pipes are intact, although could do with replacing.

No change to the problems from doing the above.

Any ideas of what to do / try / test next?

Thanks Richard

Hi Just an update. I have solved the problem on my car. It was a faulty ignition amplifier. Someone suggested that this might be the problem and I used the test detailed test here to check the amplifiers: AudiWorld Forums: DIY test of power output stage/ignition amp module N122 (long & BWW)

The full thread is: Cat light flashing / misfire - Page 4 - Tyresmoke Forums

Hope this helps anyone with the same problem.

Best wishes
Richard