Weird Idle

[GrandAmGT1996]

Ok, I have a '96 3.1v6 Grand Am GT and sometimes when I start up the car it idles really weird, if you watch that tach it will actually bounces between like 600-800RPMS and it bounces rather quickly. I notice it more now that I have my exhaust because now not only is it visible, but twice and loud because my of my exhaust. In a way it sounds like there is a miss in one of the cylinders, but I took it to autozone and it isnt throwing any codes? Help would be nice. Oh yeah, the car runs fine and if I give it a few revs when its doing the weird idle, after that it stops?

[Mike Jung]

Try:

Cleaning out the throttle body of carbon & gunk.

Clean the fuel injectors through the rails.

Change the fuel filter.

Change/Clean air filter.

Check spark plugs & wires.

[GrandAmGT1996]

I know the air filter needs changed, but I think tomorrow I'm taking out the air box and putting a cone on so I'm not going to waste any money on buying a new stock replacement...until I decide to sell the car, but that will be a long time. As for the other stuff, I'll try that.