94 rattling when stopped, started, parked, reverse..??

[Melyssa]

I took it to the mechanice a couple weeks ago because it was Reving up and down on its own in park. They said they adjusted something on the throttle for minimum idle..and it seemed okay. Drove it on the highway again and stopped to get gas and it went back.

Now it is not idling like that...but rather rattling alot. Almost like it is going to stall. I need to get up to my brother in laws so he can look at it but it is a 4 hour drive away!! I dont know if it will make it.

I looked under the hood whilst the car was on and the whole engine block (or if it is even that?? I dont know...all I know is its where they took apart to change the valves last summer)...is rattling quite a bit.

could it be something as simple as a filter? a seal or a plug or what.

Help me.

Thanks!!!