Inconsistent Idle

[denisonnd]

Hi

My car started doing something lately. When I stop at a lights my idle is about 1200 rpm (normaly 900rpm) while vacuum is higher then normal 0.72 onstead of 0.68.

If I tap accelerator pedal once idle and vacuum goes back to normal.

The confusing thing is why would vacuum increase when it suppose to decrease?

Has anyone had similar thing happen? It that just a sticking accelerator pedal?

RB25DET S2

Boltons

300kw

Link G4

I also have noisy idle control valve if that tells you anything

Car drives ok

[89CAL]

Vac will be higher when revs are a little higher. Throttle body closed and engine turning faster means more vacuum created.

Your problem is the idle. Put the vac issue at the back of your mind

What ECU, what other relevant mods? Need more info to help

[XGTRX]

I also have noisy idle control valve if that tells you anything

Car drives ok

Not confusing at all really.

I would say you have diagnosed the issue yourself.

Do the diy fix on the ICV and I think there is a high probability the issue will be solved.

[denisonnd]

Ecu:Link 4g extreme

Mods: Boltons to make 310 wheel kw inc, plenum, throttle body, fuel press reg. Basicaly everything you normally see on such set up, no short cuts

I have tightened throttle cable a few weeks ago

Changed throttle control sensor

I have a noisy (ticking) idle control valve

Can't think of any other relevant staff

I wonder if idle control valve is starting to fail, I was told it will eventually fail since it is ticking

Edited March 22, 2015 by denisonnd

[Ben C34]

Throttle cable to tight,?

Edited March 22, 2015 by Ben C34

[jiffo]

Agree, back off the throttle cable a touch before you get too carried away.

[89CAL]

Did I miss thr info about mods on your first post or did you add that :S

Anyway, I would check what the others have suggested. If you have recently tightened the throttle cable then thats where I would start. Maybe loosen the cable completely so it is not putting tension on the TB and then check your idle then. Rev the engine a little and then check again.