bad idle - MAF sensor?

[snidehockey]

Before I say anything - I've aready replaced my IAC valve w/ a brand new one.

My car's idle bounces all the time...if I'm at a light it bounces from 800 to about 1100 rpm. Every once in awhile it will drop to like 500 then pull it back up and bounce some more.

I already replaced the TPS and the IAC...cleaned the throttle body

I don't have a tune but I have a BBK CAI - BBK TB - BBK LT Headers - BBK Hi Flow H Pipe - and Flowmasters.

It hasn't always bounced but it has always seemed to idle high (1,000 rpm)

I also have a CEL for catalyst deficiency pass side but this started before the CEL.

 

[40th GT]

I also have a CEL for catalyst deficiency pass side but this started before the CEL.

How long did it take for the CEL to light up after the problem started?
The EEC can take some time to react to problems, hence the delay of the CEL.

Do you still have the original 02 sensors? I'd change those too and reset your EEC.

 

[jstreet0204]

Before I say anything - I've aready replaced my IAC valve w/ a brand new one.

My car's idle bounces all the time...if I'm at a light it bounces from 800 to about 1100 rpm. Every once in awhile it will drop to like 500 then pull it back up and bounce some more.

I already replaced the TPS and the IAC...cleaned the throttle body

I don't have a tune but I have a BBK CAI - BBK TB - BBK LT Headers - BBK Hi Flow H Pipe - and Flowmasters.

It hasn't always bounced but it has always seemed to idle high (1,000 rpm)

I also have a CEL for catalyst deficiency pass side but this started before the CEL.

There are several things that can cause a hunting idle.

Start by checking the voltage on the TPS if you haven't done so. It should be slightly less than 1 volt with the throttle closed.

If that checks out, look for any vacuum leaks. Tiny ones can be hard to detect, but try spraying carb cleaner in different areas to see if the idle changes. If it does you have a leak there.

Bad or aging o2's can cause idle problems as well. I don't know of any easy way for you to test them, so if they are old now might be a good time to get some new ones.

You can also try cleaning your MAF sensor.

Long tubes can also cause some idle issues as well, for a couple of reasons. If they aren't coated the o2's will not stay warm enough at idle. Another reason, is the o2 sensors are farther down stream and the pulse delay needs to be adjusted in the tune.

 

[joshheat25]

Yea I used to have a bouncing idle when I was in park it would do that. After my tune it didn't do it anymore.

 

[40th GT]

Bad or aging o2's can cause idle problems as well. I don't know of any easy way for you to test them, so if they are old now might be a good time to get some new ones.

So how old is too old?

 

[98V6 K.I.T.T.]

I'm in the same situation, I just noticed this the other day. My air induction needs to be tuned up though. I'm running totally stock right now so I'm going to start off with changing the air filter , cleaning the Mass Air, fuel injection cleaner, and reseting the computer...hoping that this will fix the problem. If not....sounds like I'm going to have to start trying other stuff.