I just want to thank everyone for thier help. The van was fine, it just needed a new oil sensor. $14 part and $150 labor. The pump and the engine looks fine. My man switched to synthetic last year, maybe that helped.
Ok, the Cadillac (98) Still idles roughly. The idle speed goes up and down. The engine light is on and sometimes it flashes.
Also, Some times, but not always,I hear a high pitched whistle. Maybe a vacume leak?
Somebody asked me to get the engine codes ad to post them here.
1) Cylinder 5 Misfire. This probably explains why it is so rough.
2) 02 Heated Circuit Bank 2 Sensor 1
The guy at checker said in Caddys you need to replace all of the o2 sensors at once. He said there are 4 of them and they cost $90 each. 
Thanks again everyone. Your Amazing
Sarah.
The first thing I’d do is pull out the #5 spark plug and see what it looks like. If a cylinder is misfiring, it could very easily cause an O2 sensor error.
Will do. I think my dad has a tool to pull sparkplugs with. What should I be looking for?
black/oily residue, cracks, etc. It should be a nice light brown color, and dry.
The guy is wrong about replacing all the sensors. You only need to replace the one that is bad. You didn’t give us the number though. There are codes for the sensor operation and for the sensor heater. If you had the code for the sensor heater, then the sensor would be otherwise good, but it has to be replaced anyway as its all one piece.
Next time you get the codes read, ask for the number, not their interpretation or what the “code says”. If they won’t give it to you, go somewhere that will, and buy your parts from them.