FYI-I did do a search on the issue, but didn't find exactly what I was looking for.

I went on vacation for a month, and as a result my car just sat. The first couple days of driving when I got back there were no signs of idle problems, but now this is what I get.

When I start the car it irratically idles, bouncing from 1000rpm to 1700ish. If I start driving like that, it almost sounds as if the engine is running on 3 cylinders, bogs down under accel., then kicks over like normal. As soon as I pull up to a stop light, idle is irratic again. However, once the engine warms up, it goes away. I can stop the car and start it a couple hours later and it's fine (still warm I suppose). This basically happens on the first drive of the day. The weather has gotten colder here, but I had the car during winter last year and had no such problems.

I don't know if it's a hose that is expanded and not making a good seal while cold or what. I guess I don't really know where to look. I read other posts about possibly being the airflow sensor or air meter, but I haven't messed with intake stuff really. Any ideas would be appreciated.

Engine mods are as follows:

MY03 WRX

Stock airbox/filter with snorkus removed
Perrin UpPipe
APS 3" catless exhaust
Hallman Boost controller
Worx Tuning 50/50 BOV

 

Just a first guess... Often when people upgrade their injectors and reinstall the originals after months of non-use, they have some similar issues. This occurs because fuel deposits get crystalized in the injectors after long periods of sitting around. No CEL lights for you though, eh? I would try running a bottle or two of injector cleaner (in serial, not at the same time) through one or two tanks of gas. This will clean out the deposits, if that's actually the issue.

Also, no joke, check for stuff in your air intake... like critters... all the way to the air filter.

jason

 

Thanks. I may give the injector cleaner a try. I checked the airbox already because I still have the stock air filter in there after 16k miles, which I am sure is a bad thing and can't be helping the situation. I ordered a Perrin drop in filter and I am waiting for it to arrive. However, the stock filter didn't look very dirty at all.

As for the CEL, I do have one, but I have since the removal of my cats.

 

You should get those codes read. If you got a new one, you might not know it.

jason

 

what's the normal idle for a 04 wrx? im idling at 1500 and after the car warms up, the idle drops to 1k .. is that normal?

 

Normal idle is lower than 1K...about 600 or 700 I think.

 

Stock idle is 750k. Look VERY CLOSELY at your tachometer, I'm certain you will find that you've been mis-reading it. Count the hash-marks, each is 250.

 

That's kinda what I was thinking, union rex. Maybe the BOV has gotten dirty and is sticking a little or something. I'll check it out. Thanks.

 

try adjusting the worx to the second stiffest spring setting and running 100% recir.

 

yes, i had a similar problem right after i installed my HKS BOV

 

I guess I just think it's weird that the problem would surface now. I haven't added any new mods for over six months and the car has run fine until a couple days ago.

And it is also weird that when the engine is warm it doesn't show any of these signs. For instance, when I left work tonight, it was doing the idle thing as described above. I let it sit idling irratically for about 10 minutes, then without shuting off the engine, drove for about two miles with the same hesitation and idling. At a stop light, I shut off the car and immediately started it again. It ran perfectly all the way home.

I am going to get the codes read tomorrow, but until then I am at a loss.

 

Okay, just FYI, I think I fixed it. I went to Auto Zone and had them pull my CEL codes. To my surprise, I only had one, and it was a "Low Idle Circuit" P0508. So, I searched around online and figured out it was the Idle Control Valve on top of the throttle body. I cleaned that out with some carb cleaner.

Now, idle is fine (for now, but I think the engine was still warm enough) and no CEL. I guess the test will be when I go to start it tomorrow.