#1 cyliinder miss - intermittent & can NOT find the cause

[syty1]

I have the most bizarre problem; #1 cylinder misses intermittently. The plug, plug wire and coil all check out according to TSRM, and each have been replaced to confirm that they're not the fault.

When I put the timing lite around #1wire, it's showing abnormal spark. It's normal when the engine is running smoothly & when it misses THE SPARK EITHER DROPS OR THE RATE DOUBLES! #6 is not showing any abnormality when the engine misses, so it's not the ignitor (or both 1 & 6 would miss).
If the plug were bad & no current flowed, that would explain what I see with the timing lite - but the plugs are brand new. I drove it about 5 miles on the new plugs & checked the #1 plug & it's brown instead of white, but not oil-coated - it is dry.

Completely stumped! Anyone ever seen this? Any ideas what might be the cause??
Any help appreciated.
Thanks,
David

 

[jetjock]

Have you looked at fueling for that cylinder? After all, current flow through the plasma is mixture dependent.

 

[syty1]

That occurred to me....seems to be the only thing left.
Next move is to change out the #1 fuel injector, I guess....

 

[supraguy@aol]

Or at least check the connector's condition.

 

[syty1]

Yes, I'll check it out this afternoon....thanx for the suggestion/fresh ideas!

 

[syty1]

Turns out that even tho' the #1 plug wire had no current flow & thus no spark; the problem was a faulty fuel injector. Suddenly the #1 plug fires normally!!
Thanks for the fresh ideas!!
I knew that there was no current flow thru the plug-wire, & that focused me on an electrical problem....

 

[jetjock]

Good deal. At the risk of greatly oversimplifying the plasma physics involved it helps to think of the ionization occurring across the plug gap as a resistor with the mixture changing resistance. Too rich or lean and misfire occurs.

 

[syty1]

Makes sense (as usual in retrospect)
Thanks for the help