Help: No compression in valve 6

[DavidWeis]

Hi,

I own a 95 C280 with 180,000 miles. This weekend, on local highway drive I was testing the brakes and alignment, then accelerating back up to speed. After braking hard, the engine started to bog down.

A mechanic did a compression test, and found that there was only 15psi in cylinder 6. In Top Dead Center, he tried to pressurized the cylinder, and said he could hear the air going into the intake valve. He thinks that something is keeping the intake valve open.

Has anyone ever heard of this? What could it be?

Help:

Thanks