I have a 93 Ford explorer, when I start off at a high speed I hear a rattle noise, when I'm going up a hill it starts to make the rattling noise and the check engine light comes on, also when going up the hill when this happens I'm going around 110 and it kinda like powers out slows down on its own to 80, when I have the pedal down all the way you can hear I think over drive kicks in the rattling stops but no power and when I release the pedal a little the rattling noise comes back. Also the RPM is at 4 when i have the pedal all the way down.

I hope I explain this alright, not really sure how to put what happens.

Thanks.

 

I assume when you mention 110 and 80 you are referring to KPH (rather than MPH, engine temperature, or something else). Is it possible the rattle noise is an engine misfire? When's then last time the vehicle had a full tune up? Had the vehicle been sitting for several months before this started happening (old fuel)? Have you checked the diagnostic codes to see what reason the OBD-I system is reporting to trigger the Check Engine Light (CEL)? If you manually shift the transmission out of overdrive does that change the noise?

-Rod