I wish I could be there too. It would be a no charge. As far as the vacuum hose you replaced, as long as there is no kink in it to restrict vacuum, it is fine.
This is a tough one, but we'll get it. The next thing I need you to check is called the idle air control valve (IAC). It is located on the throttle body. What is does is this. When you let off the gas and close the throttle plate, it allows air to enter the engine preventing it from stalling and maintaining a steady idle. Although a problem with this part usually causes a surge in idle speed. However, it can cause a low or high idle.
I have attached pictures of it so you know what you are looking for. It unbolts from the throttle body. At the end is a pintil that moves in and out. That is what allows different amounts of air to enter the engine. When the idle starts giving you trouble, I want you to disconnect the IAC to see if the idle changes. If it doesn't make a change, there is a good chance it isn't doing anything. I would then like you to remove it and make sure it is clean. At that point, have a helper cycle the key from off to the run position. The pintil at the end sould move. If it doesn't, and it is getting power (you can check the wiring harness with a test light), then chances are it is bad.
Try that and let me know what you find. I'm sorry I keep giving you different things to check, but doing this over the internet takes a lot more time. If I was with you, we could do all of this in a matter of 30 minutes.
Take care and let me know how you make out with this.
PS: I can't remember if I mentioned this, but the early 4.3L V6 engines did have intake gasket issues. I mention it because that may be our next check. At that point, I will explain how to check it. You can check intake vacuum with a gauge, or use starting fluid or carb cleaner to see if there is a change in RPM's when you spray around the intake. However, I would feel better if you had the spray test done by someone with experience. If the spray hits something hot enough, it can catch fire. Not a pleasant experience.
Wednesday, January 12th, 2011 AT 3:25 AM