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Thread: High Idle, Weaker Power after Boosting

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2014-09-06 15:29:32
High Idle, Weaker Power after Boosting
Hi I recently just got this problem after running my car a few times hard. When warmed up, itll idle 900rpms~ and once i go thru the gears 1, 2 and 3rd, the idle will shoot up to 1.5k - 2k and stay there. I try to rev it up in neutral to bring it down, nope. Last night I stopped at a gas station and turned it off for 10 minutes. When i turned it on, rpms went down again, maybe a leak sealed itself during that time?

There is a loss in power once the rpms idles high. Once rpms goes back down, everything seems normal again.

Car is a lowport + t25. Would a boost leak / vac leak cause this? Bad IACV? This happens everytime now.



idle is always high now. wtf and feel robbed of power maybe 90% of what it used to be, so nothing dramatic, still runs hard just not as much with this idle change, enough though to piss u off
Last edited by ser101 on 2014-09-14 at 22-53-08.
2014-09-07 11:56:27
try cleaning the iacv
2014-09-07 23:19:29
what ecu are you using?
2014-09-07 23:46:19
JwT ecu, cleaned iacv few weeks back prior to the problem. How would I go about testing vac leak?
2014-09-08 23:09:25

edit: Car is not at 100% potential, boost leak? It's not your crazy boost then fall flat on its face, it's like the feeling when you get USED to the power! only now, I'm in denial that it's that because it' definitely feels slower and i noticed it right away after running a few cars. I went over clamps, time to pressurize it i guess. Only reason stopping me is why is the IDLE so high? Could a boost leak cause that?
Last edited by ser101 on 2014-09-09 at 01-53-03.
2014-09-09 01:47:15
Block the iacv and see if it still does it. If it doesn't, then there is your problem. Or better yet, just unplug it while it's idling right.
2014-09-09 01:50:44
Originally Posted by nsusammyeb
Block the iacv and see if it still does it. If it doesn't, then there is your problem. Or better yet, just unplug it while it's idling right.

It's actualy IDLE'ing high everytme now. I just cleaned iacv again / replaced gasket.

btw how does one block iacv? id ont see a hose?
2014-09-10 23:33:22
Pull the iacv off, leave it plugged in, put your hand over the opening, have someone start the car and turn ac on/if no ac turn wheels to full lock and see if the pintle on the valve moves. You might have hurt it when you cleaned it.

If you blip the throttle does the idle hang even higher? Are you sure you have no vacuum leaks?
2014-09-12 19:13:42
The problem is that small spring inside the unit. I find the older units hold up better than the newer aicv.
Last edited by Kleensleeper on 2014-09-12 at 19-15-24.
2014-09-14 02:03:32
Thx for the replies

So today I

-cleaned maf
-sprayed whole can of carb choke everywhere possible around intake manifold, found nothing
-unplugged iacv while car ran, (idle 1300) nothing changed, what could this mean?
-disconnected batt overnight to reset things
-went over and tightened clamps

Still idles 1300-2000. Car pulls good, not anywhere near what it was tho. Bro says nothin is wrong, but before my car felt as fast as a buddies 400whp cobra, not no more. I don't care for the idle fix, as long as I get my power back but the idle is definitely related as it climbed up as i lost power
Last edited by ser101 on 2014-09-14 at 04-38-11.
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