I have been trying to get rid of the "rough" idle for a couple of weeks. I turned up the vacuum to compensate and a CEL(P0507-idle is too high) pops up. I lowered the vacuum and the car is idling like ***. I can't seem to find the "perfect" spot since it never stabilizes.

I was advised that adding cam gears helps with the idle. Does anyone know the best cam gear setting for 264/264? TIA.

Its odd that your getting a rough idle with 264 HKS cams.. usually most set them straight up 0/0.. I think Vishnu has a recommendation for those cams..

Check for other vacuum leaks before you knock yourself out..

I did a boost leak test about 2 weeks ago. No leak was found. The car idles around 900-950 rpm when it warms up, then it slowly starts to stumble on idle. From 900ish rpm, it dips to 500 rpm, then goes back up to 800 rpm, then back down again to 500 rpm and sometimes goes back up to 900-1100 rpm for a sec.

BTW, do you know if the car ecu learns the set up after a while? When I raised the vacuum to around 1000 rpm, after about a week the idle barely dipped and for some reason the rpm went up to 1100ish. That's when I got the CEL. The weather did get cooler though. Do you think its the weather or its the ecu learning?

You need an ECU flash. I have a TurboTrix flash and my idle is smoother than stock now as far as hunting and RPM changes. We actually removed a bunch of timing at idle to acheive this. Most people add it. There is such thing as too much.

My car was road tuned by Al about 2 weeks ago when he was in Houston.(let's not start again please ) It has been idling like that before, during and after the tune.

Another question: Let's just say that there might be something wrong with the cam install, do y'all think that this would be one of the symptoms?

i have severe stalling problems with stock cams... maybe if someone could point out how to fix it on your setup, i could try it on mine..

Try -3 intake, -1.5 exhaust.

That's really odd that your idle is fluctuating. Mine is dead steady after Al's custom flash. The guy getting tuned after me had the same cams as mine and yours and couldn't believe mine was cammed. (if you stand behind the car, you can still hear a slight bit of lope)

This may sound simplistic, but have you tried replacing/cleaning your air filter?

I have the BR Air Filter Kit and I haven't really cleaned it since I bought around summer time. I'll give that a try later today.

BTW, regarding the guy that was tuned after you, how was his car idling? Same as yours?

His car's idle sounded pretty unstable when he pulled in. We were tuned late in the evening, so I didn't stick around to hear his car after the tune. I've heard a couple of cars with the 272 cams that were adjusted to -4/-1; and that's what this guy's car sounded like. I don't know how guys here say that it idles close to stock, because in my estimation, it doesn't. The rpm gauge may be pretty steady (mine was before the idle flash upgrade) but you could certainly feel it stumbling and most certainly hear it. It basically sounds like a cammed car. Some people like it, others like myself, don't really car for it.

When I say that my car idles like stock, it does. You can only tell my car has cams if you stand behind it. If you know what to listen for, you can tell. For the average enthusiast, let alone average driver, they will not know I've got cams.

Also, do you have cam gears? If so, what brand? It's possible that the cam install was fudged up. Open up the cam gear/timing belt cover and check. What did Al say when he tuned your car? Did he feel the idle was normal?

Oh, also, you should check your MAF to see if it's plug is fully seated, and also check the sensor if there's any oil film on it. Sometimes K&Ns come with too much oil and can adhere to the sensor, thus throwing it off.

Since you did the boost leak test, check your vaccum lines going to your boost guage, BOV, etc. Maybe you have a leak past the TB?

I don't have cam gears yet. I am planning on getting the HKS gears. When Al was tuning my car, he stated that there was something wrong with it...something electrical according to him. I asked him if the installation of the cams could be the problem and he stated that more than likely it was not since the car was running fine and pulling hard. The only problem was the idle. When we would pull over and Al was punching numbers in his lap top, I can see that the car idles around 14s and when the rpm drops it richens up to 12s.

I checked my MAF when I took my intake apart. I was dry since the BR Air Filter Kit does not have any oil.

I checked pretty much all the possible lines but I'll do it again maybe I've overlooked something.

BTW, here are my mods:B&B TB with UR High Flow Cat, Walbro, 264/264, Halman Pro MBC(20.5 psi), NGK BR7ES(gapped at 23), BR Air Filter Kit and DynoFlash custom tune.

I went and started adjusting the vacuum again. Is 1025ish RPM okay or it is too high? That seems to be "the spot" for now with very minimal dipping in the RPM and almost stock like idle. That's with the fan off. With it on, RPM drops to an even 1000 RPM. With AC and everything on, it drops to 850-875 RPM.

Like I said, you need to remove timing at idle. My car was doing the drop RPM thing also and it is fixed now. You don't need to mess with the idle adjuster screw.

I will be purchasing the HKS gears tommorrow and I will be retarding timing(-3I, 1.5E) as mhgsx advised. Hopefully that will be the end of that. What RPM are you idling with your TT flash?

850-900

I find my idle hunts every so often.. Its hard to tell with my car simply because of how the airflow sensor is setup on my car.. But sometimes something affects the velocity of the airflow and can affect the idle.. 1000rpm or so can't hurt, it allows the car to draw a little more air and reduces the fluctuation of airflow that can cause idle hiccups..

Out of curiosity, what kind of DV/BOV are you running, Stock?