What can be the cause of a 94 Saturn that has a vibration and noise like something that moves up and down has sloop in it?

Answer 1

Coolant temperature sensor will cause an idle variation and if not repaired soon enough will foul plugs to give a rough idle. These are real common on these cars as they crack.

AnswerYou might also have the right upper engine mount checked. The vibration from the engine will make it seem like your car is idling up and down depending on the freqency of the ressonance. It will especially resonate when it is cold because of the higher idle required for cold starting. If you attempt this yourself, the mount is bolted to the top front edge of the block and has three bolts to the engine and an arch with two nuts holding it to the right front fender well. Don't forget to put a jack with a board under the engine oil pan, and put just enough pressure to take the tension off the engine mount. Don't put too much pressure on the oil pan though. The part costs about $48.00 at a local parts store.

ANSWER

The answer above is most likely the problem. A very common issue with these cars is how they eat up motor mounts like crazy. Check the motor mount on the upper passenger side if the vehicle. If this mount is collapsed I can assure you the others are as well. If you do not repair these soon, binding and stress is induced onto the entire drive train system. This can cause thousands of dollars of damage down the road. The vibration being allowed with collapsed mounts will cause the appearance of idle surging, when in fact this may not be the case at all. Number one thing to check is your motor mounts. You can replace them all for about 100 bucks in parts taking into consideration you replace them yourself. Good luck.