Thread: Rough idle

I would clean the MAF and check the IAC (idle air control valve). If its sticky or defective it will screw w/ the idle. And yes, plugs/wires can cause this as well. So can a vacuum leak but usually a vac leak will cause it to be this way all the time.

Might be time to check the PCV as well. If you replace it be sure to install the o-rings properly. One goes on the base of the PCV itself, and the other goes inside the lip of the UIM where the MAP sensor sits on top. This can cause issues if not sealed.

Is it possible for bad gas to do this? Reason I ask is, I had the same issue this morning at idle, then went to get gas at my usual station and found it was closed and out of business. I just got gas there three days ago and today everything is gone. Since filling up at a different station I've had the car on/off at least 10 times and the rough idle hasn't come back. I'm thinking my old station just pumped the tanks dry the other day before they closed down and I got some bad gas out of the bottom or something. Crossing my fingers....

Very likely you got some junk in the tank then. Probably had some water in it. I'd run a full tank through it and maybe throw some Seafoam in as well and see what you get at the next fillup.

I'll be keeping an eye on it, probably stick some seafoam in the tank next weekend. So far the issue hasn't been back since gassing up at a different station. Can I still get codes without CEL on?

I grabbed some TB cleaner too, figure I may as well clean the TB while I'm at it; any particular procedure for removing the intake screen thats in front of the MAF? I don't want to break anything and I've never cleaned TB on one of these.

Only one- DO NOT REMOVE THAT SCREEN!!

Besides that, nothing special, but you will need a TB gasket in order to bolt it back on. Remove the MAF before you clean the TB and take out the IAC and clean it as well. Make sure to get the butterfly clean as possible as this is where it likes to stick open a bit causing wierd idle issues and whatnot.

there isn't a snap ring in your maf?

the older cars had a snap ring to hold it in.

I don't know what's in there, I haven't done anything yet. I was just wondering how to get the screen out so I could give the TB a quick clean out while I'm doing the MAF, without unbolting the whole TB from the engine... I'm just concerned with possible sticky valve from buildup (and I don't have 10mm socket handy anyway). If it's as simple as popping it out with my finger from the MAF hole and doesn't require a new gasket or something around the screen, then that's all the info I need. I've never cleaned a TB that had a screen there before that's why I ask.

sticky throttle blade?

You need to remove the snap ring without damaging the screen.

Or IAC valve?

IAC passage mostly has to be cleaned from the outside.

I'll clean them both out as long as it can be done without actually removing the TB

Just don't fill your intake up cleaner and then start it

Good to know hopes and dreams are still out there doing good work.

Just one more question before I begin; do I need to replace IAC o-ring? Because if that's the case I may as well just get a new IAC for $20...