Hey there, and good afternoon.

There's something weird about my idle.... but only sometimes.
Start ups are normal, start high and level off around 750-900
Driving is normal
When I sit at a stop light it might bounce. I am sayin "might" because it does this maybe half the time, and the other half it would be normal idle. The bouncing is always rhythmic and pretty much the same rpm range and pressure range.
RPM: 1200-1800 constant rhythmic surging.

I hate the fact I would be at a light and ther person next to me would think I am an *** revving at them. I accutally do get people revving back at me too

This is what Im thinking, but I am asking for everyone's input that can help me out:
I think it may be the MAP sensor, since my idle and both throttle vaccum pressure is surging together at the same rate. (according to my VAFC)
I also might be thinking about timing, although I admit I don't know how they corelate; I am throwing this out because my car has been tuned last year but is running well yet the timing was greatly retarded, so maybe go in for a tuning soon, but not before I get some input from you guys.

Im sure it is not (for I have checks these):
Air in coolant
Dirty IACV
Vaccum leak

Mucho Thanks!

 

I had this same problem. Then I reset my ecu and also pulled a few fuses under my hood. Now my idle is hard and rough and I will range from 400-500 I can not get it up to 750. I changed the cap and rotor today that seemed to help a little but my idle is fucked. Sorry to jack your thread.

 

No, it's cool; I got a suggestion for you.
Have you tried adjusting your idle screw valve?
It's on your throttle body.
Use a flat head and screw it in for lower idle (I think) and out for high idle (Or other way around)
Then you have to reset the ecu.
See if that helps.
This has nothing to do with my problem for my idle is fine when it is normal but can be a bitch at times that are unexplainable.

Anyone else?

 

Yes, I already tried that and it has very little effect on my rpm. Any other suggestions?

 

https://honda-tech.com/zerothread?id=666256

 

Heres another good one.

https://honda-tech.com/zerothread?id=741561

 

could be that the IAC needs a good cleaning and it could be just some air in the water lines.

I'd start off with removing the IAC, cleaning it out, and resetting the ecu. Also try running the car from cold with the rad cap off, and let the water cycle a couple times- thermostat will open and hopefully water level will drop a bit

 

https://honda-tech.com/zerothread?id=741561 That is a damn good thread

I think I'll try to choke my IACV TB hole tonight see if I have a vaccum leak which I am sure I do not.

 

Bump for more opinions

 

Dont think i saw you mention TPS sensor? Check that yet?