A Lower Gwynedd man has been found guilty of homicide by vehicle while driving under the influence, and other offenses, in a crash that killed a friend who was riding with him. 23-year-old Matthew Lynch was going nearly 100 miles per hour with a blood alcohol level more than twice the legal limit when he crashed his car on Swedesford Road in Upper Gwynedd.  20-year-old front seat passenger Isaiah Washington of Philadelphia was killed in the early-morning crash in January of last year.  A crash reconstruction expert found that Lynch’s Honda Civic left the road and became airborne on Swedesford Road near North Penn Oak Drive, struck an embankment, flipped over and hit a tree.  Lynch and a back-seat passenger, 23-year-old Tyriece Smith, were seriously injured.  Smith testified Monday in Montgomery County Court, saying he told Lynch to slow down.  He said the three men had been drinking at a Blue Bell area bar prior to the crash.