500 rpm fluctuation....please help!!

Teaks92HB · Post by **Teaks92HB** » February 08, 2008

Ok so today my car ran fine. i installed my 6x9's in the rear hatch and i noticed about half way home from work that my car at idle was fluctuating rpm, i have no tach and can only guess. it seems like it is jumping about 500 rpm. now when i shit it off and start it it runs fine, as soon as i throttle and let off it starts.. anyone have any idea?? please??

93ludeSi · Post by **93ludeSi** » February 08, 2008

could probally be a number of things. cheap fuel, bad plugs, bad wires, vacuum line(s), idler valve, pretty much anything ignition or fuel related. doubt installing new speakers would effect idle though. when's the last time you did a basic tune up (injector cleaner/new plugs/plug wires/air filter/etc.) ?

any other parts you installed/removed lately?

Post by **Nikku** » February 08, 2008

first thing i would check is vacuum lines

boostjunkie95 · Post by **boostjunkie95** » February 08, 2008

Idle Air Control Valve may be dirty?

Post by **Nikku** » February 08, 2008

IACV could be dirty or one of the o rings inside of it could be fubared. i remember on my CRX it took forever to chase down my idle problem, i checked all the vacuum lines they all checked out but i changed them anyway, then i changed some other random parts and it ended up being the weird ass piece thats on the upper front (IE side closest to the engine) of the IM.

also, a fluctiation like that can also be caused by air bubbles in your cooling system. depending on the severity of the bubbles you would probably notice the car running a bit warmer then usual all the way up to overheating.

Teaks92HB · Post by **Teaks92HB** » February 08, 2008

nope its all stock. it's weird it only does it after i give it throttle. it runs fine during load. maybe i should just drop the LS from the other car in it.. gives me an excuse

tommybanzai · Post by **tommybanzai** » February 08, 2008

its winter...gas is shitty and full of dirt and water...gets some ISOfreeze...or something like it that will break down water in your gas...its cheap (only like 2dolla)...toss it in tank....fill tank...give her a few dozen miles and see what happens. just happened to me.

Teaks92HB · Post by **Teaks92HB** » February 08, 2008

kk, yeah i am beginning to think it was a vacuum leak. but i'll give that a try.

EK29K · Post by **EK29K** » February 08, 2008

updates? you figure it out

Teaks92HB · Post by **Teaks92HB** » February 09, 2008

not yet no... its weird as hell. checked vacuum lines, sensors, the basics and the all seem fine. but thats just from a visual. At cold start it is fine, but once it warms up it acts up only at idle after given throttle. But that only lasts for a little bit. it actually clears itself up. It hasn't thrown any codes yet which I'm great full for b/c checking codes on obd-1 sucks!!