'04 NB2 idle issues

[— Agent☣Orange —]

As for the rattle, check where the aluminum heater core lines enter through the firewall for contact.

[joe morreale]

I had issues very similar to yours. No codes. What turned out to be was a failing MAF. See if you could borrow one from a friends car to test. I bought my replacement used for $40. That was 3 years ago and no troubles since.

[HarryB]

Thanks Joe! I eventually found out that I had a cracked cam cover breather hose. I replaced it and nothing has happened since. It may be random, it may not. Waiting till it starts again to start testing stuff.