Feel free to move this post if it is in the wrong place.

I have an 6MT 05 G35. I noticed this issue a few months back but can't seem to find a fix/reason for it. My car is only blowing heat while moving, or if I rev the engine in neutral. While sitting still it blows cold air. Has anyone experienced this and/or know what it could be?

Thank you!

 

Air bubbles in the cooling system.

 

This^^ you need to bleed your coolant. It can be a pain on the G though so keep at it until you get hot air all the time.