1999 Le Sabre misfires engine light on and off
Car began missing during a ong drive two weeks ago. Minor missing with no check
engine light. Progressively got worse. Checked for vacuum leaks, none. Coil pack,
has constant flashing using spark indicator. Check engine light came on with code
p0300. Irregular intermittent misfire. Last July 2014 I replaced the upper intake
manifold with new gaskets on the lower.New PCV, IAC and MAP. The car ran great
for 8 months. Changed Mass air flow 3 years ago, ECM 4 years ago.The plugs had
over 80,000 miles so I changed them today. One was cracked #6. Now the car runs
very bad with a flashing check engine light. I shut down and I am looking for help.