Halfway leader Jimenez saw his hopes nosedive with a string of errors. Four bogeys in the first eight holes saw him slump to one over but after recovering with birdies at 9 and 13 he dropped four more shots coming in to finish at three-over.
Scotland's Martin Laird saw his hopes of a famous home victory go up in smoke when - just one off the pace - he ran up a nine on the par-four third after taking two penalty drops from the heavy rough.
He eventually signed for an 81 which saw him spiral down to tied 51st.
Hideki Matsuyama's chances suffered a more controversial blow as the 21-year-old, who only turned professional in April, was penalised a shot for slow play.
Matsuyama was given the penalty on the 17th, turning a par five into a bogey six and a round of 72 that left him three over par.
It is the second such penalty issued in a major championship this year after Chinese schoolboy Guan Tianlang was penalised during his second round at the Masters.
