The Yorkshire side, pre-season relegation favourites, stretched their own run to five unbeaten with a super show.
But leading scorer Howard, rated at £3million as he attracts Premier League attention, lived up to his price tag with a stunning opener.
It came after 67 minutes following an astute ball from Peruvian Miguel Mostto and Howard kept his head to side step a challenge before curling in his sixth of the season.
Four minutes later the game was out of City's reach when keeper Adriano Basso couldn't hold Dominik Werling's blistering 30-yard free-kick and Dennis Souza lashed in the follow-up.
Sub Martin Devaney rounded off the night three minutes from the end when he smashed in an angled shot after Howard's super pass.
Barnsley turned in an impressive performance and could have been in front in the first half.
Werling, back from suspension curled a fabulous cross from the left and when Mostto headed down, Grant McCann forced a fine save from Basso when hit a long-range shot.
Basso had to drop low to hang on to Mostto's shot from the edge of the box when Howard produced a first-time effort and moments later the Barnsley midfielder was hunting again, hitting a 25-yard shot on the run that Basso did well to hold onto.
McCann came within inches of a spectacular goal from a free-kick after 32 minutes to add to his pair of carbon copy strikes that helped Barnsley to a win at Southampton.
But City came close to grabbing the lead after a neat build-up when the ball broke to Marvin Elliott, only for Heinz Muller to stretch and fingertip over. Darren Byfield then flicked an inviting header for Scott Murray to produce testing shot.
Ex-Barnsley winger Michael McIndoe was roundly booed, but in first-half stoppage time he almost silenced the home fans with an accurate corner that brought a power header from Bradley Orr that was inches over.
Early in the second half Barnsley skipper Howard came close to breaking the deadlock as the home side continued to grab the lion's share of chances.
But then came the home side's three-goal blast that left City shell-shocked and unable to produce a response.