[fitz04]

Replaced a rear head gasket on my 2003 Taurus,have no codes but engine runs and idles rough,checked the three back plugs,and coils,(Cop's) they r not firing, also switched the 3 back coils and plugs with the front 3,there is no change.
hope someone can help with where to go from here.car is running on 3 cylinders,thank you in advance

 

[Boghog]

Well to start with,if you had 3 out of 6 cyl not firing,you wouldn't be running.I'd start by check for engine codes,there must be some,and start rechecking the work that you did.The most probable cause is a vacuum leak,Whether is be a hose off or put in the wrong place or the intake intake set leaking.Try to retrace your steps and visualize what you may or may not have done.:idea: