A4 revs fine, but sputters under a load

[AZ A4]

I have an 2005.5 A4 that revs fine, but sputters under a load. However, it drives fine if you stay under 2000 RPM. The code came back as P0300 (misfires). I don't understand why it will rev to redline in neutral, but not in gear. I have replaced the coilpacks, and the problem remains. Thanks for the help.

[JohnBoyToo]

I am completely new to the Audi engines, but have heard that carbon buildup is notorious in the TSFI engines...

good luck and hoefpully someone can help.

[ezveedub]

Originally Posted by AZ A4

I have an 2005.5 A4 that revs fine, but sputters under a load. However, it drives fine if you stay under 2000 RPM. The code came back as P0300 (misfires). I don't understand why it will rev to redline in neutral, but not in gear. I have replaced the coilpacks, and the problem remains.

Thanks for the help.

It could be your FSI pump is not pumping out enough fuel due to a worn out FSI lube on the camshaft. If you remove the FSI pump and bucket, and the bucket is worn or rubbed through, you need to replace those parts and the camshaft. Unless the FSI pump shaft end is damaged, you don't need to replace it. Usually its the bucket and camshaft only.