I have had my Accord for almost 9 months now. Every time I come to start the car when its cold it accelerates and decelerates once I ignite the car. I have also noticed that when I put the car in D4, D3, L, or R it stops and acts normal. But, when I have the car in P or N it does what I explained above. It does this until the car gets warm and the gauge on the dash starts rising. I need to solve this issue. Don't be afraid to tell me if its a transmission, or anything else that's big.

I have replaced the MAP sensor because it was giving me a check engine light and reset the light afterwards, I have also replaced the Idle Air Control Sensor because that's what my mechanic told me it might be but it didn't change it at all.

I am just getting really tired and worried about what this could be. Thank you in advance for your help and just HELP ME PLEASE!

 

Honda IACV failure is not as common as just being dirty and/or the idle-control system being adjusted. Vacuum leaks, air in the cooling system, & a few other things can cause it too.

Try this:
https://www.hondaaccordforum.com/for...e-speed-38734/

 

Jim, I have done this aswell and it still didnt do anything. Sorry I forgot to mention it above.

 

So the idle is fluctuating when the engine is cold?

If yes, then open the common diy thread on top of the gen tech forum. There is a link for FITV testing. The first test would be to plug the lower port with your finger in the throttle body when the engine is cold and running. Does the idle stabilize?

 

I will give the FITV a look and see what I can come up with. And then I will let you know for sure. And the idle does stabilize once the car gets just a tad warm.