I cant find the oil pressure switch on my 1983 Cadillac seville

did you put the plug back in the sump or did you remember to put the correct amount of oil back in the sump oil
sender problems will not occur just like that after an oil change

unfortunately your forward clutch has more than likely burned out,
If reverse works fine, that's your problem

This answer covers 1999-2005 Cadillac Deville, Eldorado & Seville.
Example Engine:
2002 Cadillac Seville STS 4.6L SFI DOHC HO 8cyl.

This engine has (2) Crankshaft Position (CKP) Sensors: the Upper sensor is CKP sensor B, and the lower sensor is CKP sensor A (this is included for the OBD-II DTC codes - P0385 references Sensor B = upper CKP sensor, whereas P0335 references the lower CKP sensor (sensor A)).

Both crankshaft position sensors are located in the front of the engine just above the oil filter adapter. To access both CKP sensors, jack up vehicle on the passenger side, remove the oil filter, and the oil filter adapter, including the Engine Oil Pressure (EOP) switch. See illustration.

The ARROW points toward Front of Car.
1. Upper Crankshaft Position Sensor (B).
2. Lower Crankshaft Position Sensor (A)
3. Engine Oil Pressure (EOP) switch
4. Engine Oil Level switch
The Oil Filter is the can-type object below the oil filter adapter, which includes the EOP switch. Recommend: remove oil filter with an oil filter socket/strap wrench, since it's close to the oil pan.

A/C SYSTEM OIL TYPE 1983 Cadillac Seville 4.1L TBI 8cyl The A/C System Oil Type

SEE NOTE Ask about A/C repair & diagnostics DVDAll vehicles originally equipped with R-12 Freonwill require a complete system flush,draining comp A/C SYSTEM OIL CAPACITY 1983 Cadillac Seville 4.1L TBI 8cyl The A/C System Oil Capacity 6.00 Ounces

ressor oil & ultimatelyretro-fitting the vehicle to R-134A refrigerantand the compatible polyalkylene glycol (PAG) oil.

this could be a fuel pressure problem or volume problem.if its to low and you push on the gas pedal you are opening the injectors longer to allow more gas to flow.it could also be a stuck open egr valve causing a vacuum leak stalling the car at idle.the popping sound you hear sounds like either one of these,lean running condition.

the northstar engines are notorious for rear intake manifold leaks, leaks down rear of engine and looks like rear main seal. Also check oil pressure switch for cracks

Probably not. Make sure you have a clean oil filter and check the oil level. Also, make sure the oil filler cap is secured.

never come across this before and i would need to see the engine layout to work out what could be causing it but if its low oil pressure then add a tin of STP or wynns and see what happens

under the ignition there is a button turn key and press button

o did i mention you need to remove colum cover too

Oil change warning light may be on from bad oil pressure sending unit or oil switch.If they are not bad or have been changed,unplug battery for one minute then reconnect