Occasional Misfire Starting and Continuous Cranking

[peter3980]

Hi all, I have an 07 Sienna, and twice this winter have had a misfire code when starting the van. Once was P0306, the other was P0304. The van started rough and ran rough both times. If I turn it off, to try a "reboot" both times I have then had trouble starting it, and when I release the key from "start", the starter keeps cranking the engine over for a few more seconds.

Both times it was cold weather, but not unusually cold for these parts(today -10C, 14F). In both cases, I turned off again, and it started fine with no light and no bad running symptoms after that.

I suspect this is going to be hard to diagnose if the problem fixes itself and goes away, but does the starter continuing to crank on its own suggest anything perhaps??

Thanks,
Peter

[tbalon]

Your van's starter is operating normally... that is to say it is designed to crank the engine automatically untill it starts or for 30 seconds, whichever comes first. Have you ever tried just turning the key all the way and then quickly releasing it? In other words just bump the starter and don't hold the key in the cranking position. The starter will continue to crank until the engine starts or for 30 seconds if it does not start right away.

As for the misfire... depending on how many miles you have on your van... my guess would be a bad coil pack or if you have over 120K mi. then perhaps some new sparkplugs will solve the problem.