98stang1

I have a 98 gt with a idle problem.
I checked for vacuume leaks, put a new idle control thing on, I don't have cats so I put a set of mil eliminaters on it.
I baught the car and the person replaced the original mustang motor with another 4.6. The heads say its not from a mustang.
It only starts to idle when it's good and hot,
It dosnt do it on a cold start.
Can someone please help me.
Thanks.

98stang1

Also it may run perfect for a couple days, then start idleing up and down when you come to a complete stop. I'm new to 4.6 motors and really need some help. Thanks

mustang_bluemustle

Have you checked the Idle Air Control Valve?

98stang1

Yes. I've replaced it

mustang_bluemustle

Did you put the mil eliminators on the upstream or downstream sensors?

98stang1

Rear O2 sensors. Scanned it, mils are working.
I also cleaned the throttle body.

Shampue

Bad plugs? Is it throwing any codes?