Check engine light code 46? the guy that changed my oil said it was a loose bolt behind the engine or drive shaft.. I am not sure about the code number if I remember correctly.

Check engine oil level. If level is ok, check oil pressure with manual gauge. Sounds like it's loosing oil pressure. What's the mileage on the vehicle?

Have you ever replaced the timing belt?? If not the problem is likely to be a loose worn out timing belt. A floppy belt will play havoc with the sensor signals and trigger a check engine light and a camshaft sensor code.

Your check engine light---indicates a possible system failure,nothing to do with oil
You have it checked for codes,diagnose the issue and repair

Your oil should never be low.
If you go as much as 5000 miles on an oil change and really drive it hard,you may loose a 1/2 qt in 5,000 miles

Changed the timing belt and knocked loose the wires or connections to the sensors on the mass airflow device.

2002 Oldsmobile Aurora V8-4.0 Replace Crankshaft (Sensors) A and B This car has 2 sensors 1- Raise and support car. 2- Remove the oil filter adaptor. 3- Remove crankshaft sensor electrical connector. For specific CKP sensor identification. 4- Remove the crankshaft sensor retaining bolt. 5-Remove the crankshaft sensor. NOTE= Inspect the CS sensor o-ring for wear or damage, if problem is found replace it also. 6- Lube O-ring with clean engine oil. 7- Install theretaining bolt TIGHTEN to 10 N.m (89lb in) 8-Install the CS sensor electrical connecror. 9- Install oil filtor adaptor. 10- Lower car. 11- Operate engine and inspect Cs sensor for oil leaks 12Perform the CKP system variation learn procedure.

first, though you mentioned no oil leaking, is there oil in the engine?
Next, if engine runs well and is not ticking or tapping, have the codes checked...most larger parts stores do this free. Once you have the stored codes you can look up what system is malfunctioning.
If engine is making any noise at all or there is no oil in it, DO NOT START OR DRIVE IT...make sure whoever did the oil change knows about this now...If someone forgot to put oil in, they may be buying you a new engine!
At this point it may be something simple but can also be very serious.(hope not)
good luck

Your mechanic is yanking your chain. (or you mis-understanding.)

Oil pressure light does not have to be "reset." There may be CODES that need to be reset but they would turn on the CHECK ENGINE LIGHT. (I think, on your car, this is picture of engine with a check mark.) If the Check Engine Light (CEL) is flashing, it means you have a serious engine problem and should NOT be driving the car without finding the reason for the light. (Around here, many auto parts store will "pull the codes" for free.)

Oil pressure light could mean you are low on oil, have a bad sensor, wire or even a oil pump. The oil pump is inside the engine.

Clean battery cables and replace bolts. The cam sensor manet will not cause it to cut off.

Misfire on Number 4 cylinder. What engine?

The service engine light DOES NOT mean change your oil. The change oil or maintence required light means change oil. The service engine light is the same as a check engine light and means that there is something (not always really bad) is going on with your motor and need someone that has a code reader to let you know what the code is. Yes that code is a camshaft position sensor code. It is located on the passenger side of the engine in the "valley" between the two cyclinder heads. Its not too hard as long as you have some tools and some skills. Its easiest to remove the serpentine belt and remove the bolts for the power steering pump. That way you can move the pump a little to gain better access to remove the cam sensor. Just replaced one yesterday on a 99 century. Hope that helps!