I recently started having this problem with my 99 rodeo. it's a v6 2wd. probably within the past 6 months, the idle has gotten more and more irratic. it will idle from 300 to
2000 back to 300 up to 2000, and so on. this sounds as if someone is in the car just mashing and releasing the gas pedal. it does all of this on its own tho. sometimes it even drops so low it dies. i believe i have narrowed this down to the upper intake manifold gasket (air plenum). a new problem has arisen within the past week and it may or may not be related to this. every time i mash the gas when i am already at a complete stop, the car acts like it doesn't want to go. it'll shoot the rpms way up like it's in neutral and then it'll jerk back down into gear. sometimes it will even do this twice before it goes forward 15 feet. if anyone else has had these problems, please respond. i'm hoping the problems are related and that it's just a simple fix. thanks for any help, steve.- posted
19 years ago