After replacing all O2 sensors and plugs, my fault code has now changed to a p0300. Car is a 2000 A6 Avant Quattro 2.8L. Car idles super rough and has no ***** at all upon acceleration until over 2500 RPM. Engine light is on and will flash at idle but usually turns solid when driving. Is this a possible head gasket issue? Or maybe Coil Pack?

Im not savy on troubleshooting problems, but i can usually replace the part that needs to be done. Any ideas where to start on fixing this?

 

Willkommen to the forums

P0300 is random, multiple misfire.

most common causes are MAF problem, vac leak, or ignition coil

check vac lines for integrity, it only takes a little crack to cause issues

clean the MAF sensor

get with someone that has a vagcom and monitor ignition coil and cylinder firing to check if it is the coil. If I'm not mistaken, your 2.8 has two ignition coils, one for each bank

good luck

-not an expert, just an enthusiast

 

@02A6Beau, Thank you for the response! I will be sure to check the vac lines and clean the MAF sensor, then proceed to the coils if needed.

 

I think what 02A6Beau is getting at is to try testing or replacing your "ignition control modules". Your car has two of them, but it has a single "ignition coil" on each of the six cylinders.

 

I'm pretty sure his 2.8 has that combination coil pack/ICM in one package thing with wires to the plugs. It doesn't have the two little ICMs to individual coil packs on each cylinder like ours.

THIS THING x2, one for each bank

not 100% sure though

 

I think you only need one. The whole thing is for all 6 cylinders.

oP change the sparkplugs 1st with the wires. If that doesn't solve it then buy that big coil pack

 

i have a 98 audi a4 with the 2.8 v6 and i have the same issue it misfires at idle and accelerates rough. ive changed plugs 3 times . coil pack twice .replaced all vacuum lines. swapped injectors.did plug wires . and i still have the issue :/ cel flashes at idle and is steady when driving .o and i have put 6000 miles on it with this problem!!!!!!!!!!

 

What kid of plugs are you using? I've read that bosch SP will not run well in our cars.

Look over the possibilities here at the Ross tech page. Check your fuel supply make sure the fuel filter isn't clogged and pressure is good.

http://wiki.ross-tech.com/wiki/index.php/16684/P0300/000768

Did you have any other codes along with the p0300?
Also try a throttle body adaptation.

And I would not drive the car with a misfire. It can destroy your catalytic converters and Engine.