I tried the 2 cans of additive and it had no effect. Since then I noticed a few things:
1) there seems to be some black dirt and grime at the seam where the upper and lower intake manifolds meet. I thought it could have a vacuum leak, but when I sprayed it with carb cleaner there was no change in idle.
2) The car idles rougher than it used to. When it's not trying to stall, and the tach is stable, I can feel the engine running rough.
3) The car is most likly to act up right when you crack the throttle or at cruise under VERY light throttle condition (less than 1/8 throttle). Whatever it is it's very sensitive to throttle position and feels very similar to a bad accelerator pump on a carb'ed vehicle. When it acts up if you put your foot to the floor it's okay.
4) When its acting up on the freeway at crusing speed the tachometer remains absolutely rock steady, but the car bucks and doesn't want to go. When it's idleing and acts up the tach is all over the place between 0 and 1000 RPM due to wanting to die.
5)When it begins to stumble at idle, just before stalling, it starts emitting black smoke out the exhaust.
Any more suggestions?
Thursday, March 10th, 2011 AT 5:23 PM