EP3 Idle unstable.


I have an issue with my ‘05 EP3. It is completely standard, 68k.

On cold start it jumps to 2200 rpm and slowly drops to 850 when at normal running temp, it used to be 1500 rpm and down to 850 well before it was at normal running temp.

The idle, once warm, is unstable, 700-1200rpm, near to stalling sometimes when pulling up at lights etc. It does the same with the AC on or off.

I’ve had the throttle body off and the ISV if free and was not sticking. Cleaned, not really that dirty for 68k, but this made no difference.

The throttle position sensor is an Acuity hall one and the output voltage is correct.

My code reader found no codes, though the check light did illuminate while using the scanner. I use the Torque App or Car Scanner, and a Bluetooth ELM 327 module.

I did a clear codes and the idle returned to its old stable self. After a run it was again unstable, which was again fixed by a clear codes, even though it read nothing?

It looks like there is a problem that my simple scans can’t detect but are able to clear? Doesn’t help find the issue though!

Any help or ideas much appreciated!


Try this, the air assist idle valve gets a bit lazy and doesn't close properly air leaks extra air in, Take the cover off the injectors (the grey shield with i-VTEC on) on the right side there is a black pipe coming from the air assist idle valve going to the manifold, get a pair of pliers and squeeze it (don't cut it) just so it's flat and no air pass through, whilst the engine is running.... if it ticks over as it should, the valve is faulty - don't replace it use the Tegiwa delete kit....
So this is the part that looks like a temperature sender, with a hose to the side of rubber intake pipe and one to the intake manifold itself? Always wondered what that was and did!

I’ll give that a try.

Thanks for your help!