One of these things is not like the others..

[Henchman]

So I'm riding along a couple of weeks ago and stop at a light. When I go to take off, all of a sudden I've got greatly reduced power. I've got to get the revs way up to keep it from stalling when I'm trying to get moving. Then, wham, I've got full power. This go/nogo keeps happening all the way home. Did a forum search and came up with the three top/easiest fixes, TPS, plugs and TBS. Did the TPS diag, no dead spots. At about 4500 mi. on my '07 I needed to do plugs and TBS anyway, so I ordered The Morgan Carbtune and some iridium plugs. Stuff finally came, I pulled the plugs and this is what I found:

Any ideas? Is this a loose plug? Would this have caused my problem?

I changed the plugs and did the TBS, took er for a ride and did not have any problems, yet.

 

[kaitsdad]

Classic loose plug!!

You got a lunch break machine. Number One Nephew Hiroshi stopped torquing plugs when the lunch bell rang.

 

[radman]

A loose plug would have a burn path along the threads-but those look clean. I think that one came from a well that gets more moisture than the others. One cylinder loosing compression would not cause overall loss of power such as you describe.

 

[Henchman]

I concur RadMan. No path along the threads. What ever it is I can't scratch it off with a fingernail.

 

[Henchman]

My concern is that I have not yet fixed the problem.

I did not have the opportunity to test drive it under the same conditions as when the problem occured. (Fairly aggressive in traffic)

If I still have a problem, where should I start?

 

[radman]

First, try to recreate the conditions in which the problem manifested itself. Could very well be that you fixed it with a tune up. Deal with the problem if and when it occurs.

 

[charismaticmegafauna]

My concern is that I have not yet fixed the problem.I did not have the opportunity to test drive it under the same conditions as when the problem occured. (Fairly aggressive in traffic)

If I still have a problem, where should I start?

You could 'bench test' a few things: check the old sparkplugs' resistances; test fire the plugs; check the ignition components' resistances -- coils. wires, caps.

Maybe the discoloration is from a bad plug-wire end-cap firing alongside that sparkplug?

Just guessing -- but, something discolored it....

 

[Rummy]

I had reported Loose Spark Plugs a few months back.

Everyone should check them...

My Spark Plug Post