High idle and something wierd

[GG RACING]

Ok people i need your brains. My idle is high, about 1500 when it first gets to operating temp but when i depress the clutch pedal just enough to get it off the sensor at the top (about 15%) the idol goes down to normal. After it runs for about 10 to 15 minutes after it's warmed up the idle will be about 800 to 900 and when I depress the clutch it goes to about 600. Now when Press the brake pedal the idle jumps to about 1100 to 1200. This whole thing ends up giving me a check engine light that just says "High Idle Speed". If someone has a clue please feel free to share.

 

[Metallic36]

Did this happen randomly, or have you done any mods/messing around with it lately? Mine is doing the same thing minus the CEL, and so far I've narrowed it down to my throttle body needing cleaned.. mine idles a bit high, but also drives itself up hills without me doing anything. (boom07)

 

[GG RACING]

No it just started randomly out of no where, but it doesn't put any extra trottle in coasting, while I am moving and i put it in nuetral the idle is about 600 (normal idle for my car) as I slow down it is fine but as soon as the car stops the idle jumps to 1200 or even 1500. It's like the stationary idle is messed up with the ecu, while moving idle is fine. I don't know if mazda's have two different idles, when i tune hondas they have both idles. It almost seems like the ecu still thinks it's in cold start mode.

 

[BOOSTR]

I can't shed any light on your issue other than to suggest that you PM slo03.5msp, he's a tech and might be able to point you in the right direction.

 

[mazdaspeedp]

maybe the butterfly valve on the inside of the manifold is getting stuck i know thats a common problem on the p5 it was a recall at mazda

 

[TheMAN]

that doesn't have anything to do with the jumping idles

I'd check the neutral switch if I were you

 

[mazdaspeedp]

lol theres a neutral switch? maybe you throttle position sensor is ****** too or you pipe is cracked on the intercooler hot side or maybe even you iac or imrc

 

[GG RACING]

But see now the problem I am having with blaming the IAC or TPS is that it doesn't do it all the time, only when the car is stopped and the clutch is all the way up. It's almost like that switch puts it into standing idle and it's always in cold start mode. If anyone knows what that switch does that would be a big help. And I have checked for vac leaks and found none and those valves on the side of the intake manifold I watched them while a buddy played with the pedal and nothing so i think its the ECU getting a wrong signal from something and making the idle higher to compensate for something, what that something is I dont know. Thanks for all your help so far guys.

 

[mazdaspeedp]

maybe try the idle screw i think its a phillips screw it may be too loose or too tight try playing with it and drive it around then loosen a bit and so on

 

[aubrandb3]

lol theres a neutral switch? maybe you throttle position sensor is ****** too or you pipe is cracked on the intercooler hot side or maybe even you iac or imrc

Yes there is a Neutral switch, and it sounds like it could be the problem. Yes it will cause the car to throw a cell if it is dicked up.