2005 Accord 2.4l when I first start it and drive, the car chuggs at 2500 rpm. I can put it in park and step on gas, rpm chuggs 2500-3000 rpm. After i drive it for 3-5 minutes, I can turn off and restart, problem goes away.
Codes P1009 and P2647
What's the fix?

 

P2647 is most often the VTEC oil pressure switch, back side of engine on passenger side. 22 mm deep socket is all you need. The inability to go above 2,500 rpm is a dead give away (plus the code of course). The is also a filter screen on the front of the engine that can cause low oil pressure if it is clogged. search for VTEC oil screen for DIYs. Try the switch first, simple job.

This is the only engine part replaced on my two Accords, each with 250,000 plus miles!