elduderino200

Hi guys and gals,

I've been getting CELs for misfires for but only after on the highway for some time. Never in city traffic. The other odd thing is there's no other noticeable issue except for the fact the CEL comes on, no shake, no performance loss, etc.

Codes: P0300, P0302, P0304, P0305, P0306
(Random misfire + cylinders 2, 4, 5, 6)

What I have done so far:

Changed the spark plugs (twice, as the first time I changed I put in NGK but somewhere I read german cars need Bosch, Japanese need NGK... So I put Bosch in the second time).
Changed spark plug wires.
Changed the coil pack.
Changed the valve cover gasket (I didn't see much oil on the plugs when I pulled them either time, but I figured why not).
Changed both upstream o2 sensors.

My initial guess would be the coil pack but with both my original and the extra (from ECS) I get the exact same codes. (also note it's a 2.8 so it's one big coil pack instead of one for each cyl.)

It drives fine around town indefinitely but once I get going for 10-15 minutes, the light comes on. Also, it used to come on once, but recently it's been flashing at me for a few seconds then just staying on. It will also only flash when it comes on, never after it has been on for a while.

1999 Audi A4 2.8 Quattro, 163k

Thanks for any suggestions. I'm really at a loss here.

elduderino200

Well I changed the air filter, cleaned the MAF, and added a 20oz of Techron just before a fillup and the issue seems to be gone.
It was probably the Techron so if anybody seems to be having a misfire but only on the highway, like me, try Techron.

jimrobertson

If it comes back consider your fuel pump. Usually you can only wait until it fails to be sure.