IOWA CITY, Iowa — Michigan’s Denard Robinson had four shots at the potential game-tying touchdown with 16 seconds left and three yards to go.  Nothing, nothing, nothing, nothing.  Iowa’s struggling defense stopped the electrifying quarterback each time, and the Wolverines (No. 15 BCS, No. 13 AP) were stuck with a 24-16 loss to Iowa on Saturday that damaged their Big Ten title game hopes.  Marcus Coker ran for 132 yards and a pair of touchdowns, while James Vandenberg added 171 yards passing and a TD for the Hawkeyes (6-3, 3-2 Big Ten), who have won three straight over Michigan for the first time in school history.  Michigan (7-2, 3-2) drove 79 yards to Iowa’s 3-yard line on its final drive. But Robinson missed on four straight throws, with Iowa’s B.J. Lowery breaking up Robinson’s final toss to seal the win.  “They showed a lot of heart,” Iowa coach Kirk Ferentz said. “It’s almost better that we ended the game that way because that’s a tough circumstance, certainly, and you’re kind of rolling the dice a little bit because (Robinson) is a dangerous thrower but also he can squirt out of there and run that ball in there.”  Iowa’s defense bent on the final drive — in fact, it nearly broke.  But a couple of calls went the Hawkeyes’ way, and a defense that couldn’t stop Minnesota in the fourth quarter in an upset loss last week did the rest.  Vincent Smith appeared to pull the Wolverines within 24-22 on an 82-yard TD run after bouncing off Iowa’s James Morris and going untouched for the score with just over two minutes left.  Replay officials, however, ruled Morris’ elbow had touched the ground. Robinson shook it off and calmly drove the Wolverines down the field.  Then, in the final sequence, Junior Hemingway’s apparent TD grab was ruled out of bounds, and Smith dropped one in the end zone on the next play.  Robinson couldn’t connect with Roy Roundtree on fourth down, sending the jubilant Hawkeyes streaming onto the field.  Robinson finished 17-of-37 passing for 194 yards and two TD passes.  “We can’t leave the game to the officials. We’ve got to do it ourselves,” Robinson said.  Coker’s second touchdown, a 13-yard run with 10:42 left, put Iowa ahead 24-9. Robinson wasted little time answering, finding Kevin Koger for a 7-yard touchdown pass that pulled Michigan within 24-16 with 7:53 to go.  Iowa, which was gashed for a pair of fourth-quarter TDs in last week’s 22-21 loss at Minnesota, stalled on their last two drives and gave Robinson one more shot to win it.  But he didn’t, and now Michigan sits a game back of Michigan State in the division race — with the Spartans holding a tiebreaker edge thanks to a 28-14 win over the Wolverines on Oct. 15.  “It’s still November. We’ve got a lot of games left,” Michigan coach Brady Hoke said. “There’s a lot of football to be played. There’s a lot of things at stake.”  Robinson led the Wolverines to a field goal on their first possession of the second half, cutting Iowa’s lead to 17-9 with 6:19 left in third quarter. But he dinged his elbow and was replaced for a series by Devin Gardner.  Robinson found himself and the Wolverines in a big hole when he got back.  The Hawkeyes took 5:27 off the clock, and Coker burst through a huge hole and went into the end zone untouched to put the Hawkeyes ahead by 15.  The upset was a huge win for Iowa after its debacle in Minnesota — a game that ranked among the worst in Ferentz’s 13-year tenure.  The Hawkeyes came out like they’d had enough of hearing about that stinker, driving 76 yards on just six plays and going ahead 7-0 on Coker’s 4-yard TD run less than five minutes in.  Michigan answered on Robinson’s 5-yard TD pass to Toussaint late in the first quarter. But holder Drew Delio bobbled the snap on the kick, allowing Iowa to stay ahead 7-6.  Iowa made it 14-6 on Vandenberg’s 1-yard TD pass to Brad Herman midway through the second — and pushed it to 17-6 at halftime behind a pair of Robinson blunders.  Robinson’s fumble led to a 42-yard field goal by Mike Meyer, and he finished the half by getting picked off by Christian Kirksey on a deflected ball at the Iowa goal line just before the break.  Michigan had gained over 500 yards of offense in three of its last four games, but Iowa held the Wolverines to 323 yards.  “The guys really had to play good team defense, something we’ve struggled with at times. We have not been the most sound at times, and given up some big plays, so it’s good to see our guys make them earn it and great to come up with stops clearly at the end,” Ferentz said.