It could be any number of things, but after you have completed the break in it is best to change the glow plug and start tuning for performance.

With your LSN, it should be flush with the darker outside circle. If you check your manual it has a picture of where it should be.

Once you have checked the factory settings, you may have to check the idle screw. Here is a link for you to look at to get these right.

http://www.traxxas.com/support/index...&cat=88&id=450

Once you have these right, then give it another go. If it still plays up, it may be you got a bad glow plug, try a new one.

Also, while RCTech is a great site for info, you can also get a lot of info on your revo from www.traxxas.com and the revo forums under the knowledge section.

All the best.