I have this problem. It only happens from time to time. When the car idles, the rpm starts to jump a little about 500 to 700, then it starts to go from about 800 all the way down to 300, jumps up and down, and if I wont give it a little gas , it will die out after about 5 secs. I replaced MSD wires and NG spark plugs about 2 years ago. What could be the problem ?
Thanks

 

Anyone ?

 

what mods are done to the car? If you have done anything major (headers, eliminated cats, cam, etc.) to the car you will need a tune. Without a tune your a/f ratio will be all over the place making the car run rough. Another thing it could be is 02 sensors taking a **** on you. I would double check for either of those first. Also....is it throwing any codes?

 

Check for air leaks.

Cracks in air to manifold or to MAF cause that kind of stuff.

 

See the car started doing it after I did the trans on it. I didnt have any problems with it before. As far as codes.. hell yeah. YOu might be right with the O2 sensors. Ill check that.