A drug dealer who slammed his sedan into a plainclothes detective at a Staten Island strip mall last winter was convicted yesterday of assault.

A jury found Joseph Goepel, 25, guilty of hitting the DA Squad investigator as the cop walked toward Goepel’s car outside the Manor Heights Shopping Plaza on Jan. 28.

The officer suffered injuries to his knee, hand and both arms.

Goepel and an accomplice, Frank Cosentino, 18, were busted two miles away in possession of a vial of Ketamine, a pet tranquilizer, and 50 pain pills.

Goepel, also convicted of drug possession, faces up to seven years. Cosentino has pleaded guilty to drug-related charges.