Help! RPM up & down during idling

..and moving!

Friends,

My car is having some tricky problem lately. History:

While driving (highway), suddenly I feel the car is a little jerking when I step off the gas. The same thing happen when I step on the gas. In other word, it is not smooth as usual.
After sometime, the RPM start to rise a little even I didn't step further on the gas.
In the later stage, the RPM rise until 3000 by itself. Also when in free gear.

I stop the car, keep it 'OFF' for sometime & start again. During idling, the RPM goes up & down. It's continuous up & down forever. So it goes like as low as normal idling and up to 3000 rpm. If I continue driving, the car will jerking like I step on the gas 'on and off'.

So the RPM is up & down during idling & moving.

I sent to Honda SC, they clean the throttle body & change one part (with motor) that controlled the air next to the intake manifold. Well, it's ok for like 2 weeks and the problem come back. :sad_smile:

I'm wondering if there is something else causing this problem. My car is running on F20B Auto. I have e-manage installed for nearly 3 years, I don't see any error on that unit.

Any good workshop around Shah Alam that could diagnose this problem? Any idea what is wrong?

Thanks!

Problem solved! The RACV dirty, after clean-up the engine is back to normal as usual. It could be the HKS air filter too. I'll change that too. Thank you very much guys!

If not mistaken Rotary Air Control Valve or something like that (located at the Intake Manifold). I got it from a translated website (japanese) forwarded by Aja. There is a motor attached to it that control the valve.

Which air filter is good/better? K&N or HKS? Where to source this air filter for my F20B? I know N1 at Sunway selling HKS for F20B but they don't have K&N.

I think HKS is not too bad. What when wrong was the installer did not reuse the rubber attached to the ori air filter. HKS airfilter doesn't come with this rubber. Causing gap that allow air to flow freely towards TB. Lucky I didn't throw my original one, so I just attached it to my HKS.