cylinder balance test question

[stangracr67]

Finally got my car running much better after upper 60k and replacing a bad Crank sensor. the car still idles rough. also I have done a cylinder balance test about 5 times and everytime only cuts 5 cylinders. after the fifth one it just idles at about 1600 for about 15 seconds then i get a flash, 3 sec pause, flash. seems like its not testing #6. when it does this does it cut fuel or spark? i notice that when it cuts #2 the idle goes down but it doesnt run any rougher. I know that #2 and #6 are on the same coil circuit could it be a coilpack going out. Compression on all 6 are 21-215psi.

 

[rubydist]

It cuts fuel for sure and I think spark too, to one cylinder at a time.

My guess is that your rough idle is coming from a miss on #1, as you don't notice any difference in how it runs with that one off. (The code of one flash indicates that it is not happy with the results on cylinder 1.)

Since you have tested the compression and found them good, this suggests one of the following is the problem: spark plug, plug wire, injector, coil, dis.

A look at the plug on #1 should tell you if its got fuel or not - a wet plug shows fuel and tells you to look for an ignition issue, a dry plug suggests the injector is not firing at low duty cycles.