High revs while rolling. Need Help....

[EK4 Phil]

Hi all, Need some help on a problem.

Problem:
After the car is warm 15mins into a drive. When I accelerate doesn't matter in what gear, after when I need to slow down and put the car in neutral the revs stay at the last point I accelerated to. So I'll be sitting at the light's in neutral engine revving high (2000rpm plus) until about 10 - 30 seconds and then it slowly drops down to normal idle. This has only really been happening in warm weather 25 degrees plus. The warmer the weather the longer it stays at high idle.

Fixes done:
ECU reset.
While driving and problem occurring.
Pump clutch, Pull back accelerator peddle.
The only thing that brings the idle back is when I give a short burst of Gas. (even then it might not drop straight away)

Possible cause:
I have cruise control in the car and am not sure if this is the cause as it has a vacuum hose connected to the throttle body. Also it is switched off and it still happens.

This is why I want it fixed....
Bad situation:
One instance I accelerated quickly changed gear and wanted to slow down but then the car was revving till cut out (without me putting my foot on the peddle) and I tried to put load on the car (by putting it in gear) so the revs would go down and I then put the clutch back in and again the revs climbed real quick to 8k rpm. I had to switch the car off and I started again and the car went to 8k rpm. I had to switch the car off then park. after waiting 1 min I started it again and the car was a normal idle. WTF

Need some ideas on what to do.... It's scary when your engine is revving when you don't want it too.

[Limbo]

Try cleaning out the throttle body. There is a DIY on it in the DIY section

[dsp26]

had that happen after installing strut tower bar... my issue was the accel cable getting stuck at some points... like the rubber cover grips the emtal cable inside at a certain position.

[EK4 Phil]

Yeah was think it might be the accel cable but I pulled the peddle back so wasn't sure if that was the case.

Planning on doing a test and when it happens just look under the bonnet and take the intake piping off and look at the butterfly. See what that's doing when it occurs.

[omgzilla]

I've had similar issues with my old pulsar.

1st time it happened was due to the accelerator cable. The sheath/outer casing has perished and the cable was snagging on the casing. Also used to get caught on the rubber grommet on the firewall.

Similar issue happened about 6 months later - this time it wasn't the cable.

I thought it was the springing mechanism getting caught and not springing the throttle plate back to closed. I took off my throttle and found that one of my throttle plate/butterfly screws had come out (gone into the motor) and the plate was getting wedged on the throttle body.

Like this:
http://img187.imageshack.us/img187/6582/tbcf2.jpg

Nasty!

As for your issue I would be making sure your accelerator cable isn't snagging on anything and looking into cleaning out your IACV and throttle body.

[bennjamin]

also make sure the accelerator cable isnt TOO TIGHT.
Get a 12mm spanner and lightly loosen the 2 12mm nuts on the inlet manifold , there should be a slight amount of freeplay on the wire. It shouldnt be "tight" :)

[EK4 Phil]

Ok I have pin-pionted what was cause the problem. I Disconnected the Cruise Control from the vacuum link to the Intale manifold and placed a end stopper in "to not have air leak.

See pic the circul is the pipe from the cruise control.
http://i241.photobucket.com/albums/ff211/ek4phil/010120081231.jpg

This is the Modification I did.
http://i241.photobucket.com/albums/ff211/ek4phil/01012008125.jpg

Top View of the connection.
http://i241.photobucket.com/albums/ff211/ek4phil/01012008124.jpg

I'm not exactly sure what this cable does. just know it's a vacuum of somesort what looks to be from the intake manifold to "what I think" is the air/fuel regulator. Can someone confirm this?

Anyway in the process of taking the Cruise control apart to find the cause of the problem. Just thought I'd let you guys know.

[omgzilla]

That is the Fuel Pressure Regulator on your Fuel Rail. It gets vacuum from the inlet manifold in order to control Fuel Rail pressure.

So now that you've disconnected your cruise control and just blocked off the vacuum line to the cruise control module, your high rev problem has been resolved?

[EK4 Phil]

Yes That's right the problem is fixed temporarily but I believe I have a vacuum leak in the cruise control somewhere.

Thanks For your help.

[omgzilla]

No problems.

Here is a post I made about Vacuum leak detection:
http://www.ozhonda.com/forum/showpost.php?p=1481657&postcount=15

Might be worth a read (if you don't already know how to find vac leaks etc).