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Bouncy Idle, puzzling and annoying

Posted: October 22nd, 2010, 3:31 am
by MrMazda92
I fixed one problem with my transmission, by making changes to my idle. Here's the new problem that seems to have come out of it...

I was running my idle at 1,300 for easier driving during busy traffic, so I wouldn't need ANY throttle to avoid bogging.

I recently dropped it back down to 700-900ish, thinking it had to do with the whining problem I was having. It's never consistent, but always in that range. Everything off, no hvac/radio/lights/anything, fully warmed up it still varies between 7-900 rpms, it has always been about 200 variable RPM, since I've owned the car.

I originally thought the ticking was sticky lifters, so I ran an engine flush through with cheap oil, heated to operating temp and let it idle for a while, and then drained. A ton of crap came out, I did another change with Castrol 5w30 Full synthetic(I always used 10w30 before to great effect), and a Napa Gold ZR1 filter. It ran stronger than ever, but the "ticking" got a great deal louder(VERY likely due to the thinner oil). I'm now inclined to believe it's the friction gear spring, as illustrated in Ryan's thread here: viewtopic.php?f=15&t=75440" onclick="window.open(this.href);return false;

The thing is, it ticks when cold... barely. When warm, it's as loud as that video shows. I get dirty looks everywhere I go, and I honestly don't have a schedule that is consistent enough to set aside time and check it out.

The whirring hasn't been a problem since I dropped the idle. However, the jumping is present about 75% of the time, where it was about 5% before... Initially, it only happened with my heater on recirculate, 2/4 for fan speed, and temp in the high end. That was the only circumstance where I had a bouncy idle... Now it's randomly occurring(so far as I can tell), and I've tested it carefully by driving with every variable I can think of.

Honestly, it sounds like there's a vacuum leak... but it will jump for 2 hours 1 day, and then be perfectly normal for a week, and then do it again. I haven't been able to diagnose the problem, and it's occurring more often now(Cold weather maybe?)

I've looked around, and I haven't found anything that seems to match the problem, hopefully there's some either blatantly obvious or terribly obscure fix that I haven't thought of.

Thanks!

Re: Bouncy Idle, puzzling and annoying

Posted: October 24th, 2010, 12:42 am
by stereoking15
I know that a cracked or ripped intake boot after the vaf can cause this as well as an intake leak but you can generally find those quick and usually not on our styles of intake since they use a metal gasket. Also check vaccuum hoses annoying but neccessary, use ether to check for those usually car will die a little when you find it.