Anybody the reason or cause that when i start my 01 Explorer , the engine revs real high and now i'm starting to hear the engine make some noise since the oil hasn't circulated, not sure if it's a knock or maybe from the valves....

A high rev often means a vacuum leak, air is getting in from sources it should not. If it has a vacuum brake booster, that is a large line, PCV system. Even intake manifold gasket. Or, there are various sensors that could have gone kaput

dave,, would any of the problems you describe leave a " code " ?

Even though no " Engine light " coming on ? Very frustrating, I've taken care of this vehicle since day one, It has 170,000 on it and still runs brand new, now I cringe every time i go to start it....

That is curious that with the problems you describe that the CEL didn't come on. Some cars, yours I am not sure, it will come on triggered by mileage alone to remind you to have it serviced. I wish I could do better, be more help, but as you can imagine it's very difficult to diagnose these things not being at the car.

Thanks Dave,, Gave me starting point..... Greg

You are quite welcome...for nothing I feel like. I really do feel frustrated myself on this Greg.

Ehhh,, no problem... I appreciate it.... I'll look you up and let you know how i make out with this... Thanks again !