What kind of gas should i use? I have a 2002 Saturn SC2--just bought it used and I forgot to ask what gas it takes--reg, prem?

ask the dealer or , go there and see part for the car there
and see what transmission it is, for 2002 the move to 2003
and see if the same (gm parts)
there are 2 engines used, why post at all lacking such a key fact?
2.2L or 3.4liter, v6 is latter.and transmission vary buy engine max power torque, and more, gear counts for economy.

Oldsmobile Alero
or ask any engine rebuilder selling engine that (ever google that)
Or ask the shop doing it.
I'm there now. gm parts.
2002 , 2.4L 89059799 sku
fits all these

2002 Chevrolet Cavalier Base, LS, LS Sport 2.2L L4 - Gas 2002 Oldsmobile Alero GL, GLS, GX 2.2L L4 - Gas 2002 Pontiac Grand Am SE, SE1 2.2L L4 - Gas 2002 Pontiac Sunfire GT, SE 2.2L L4 - Gas 2002 Saturn L100 Base 2.2L L4 - Gas 2002 Saturn L200 Base 2.2L L4 - Gas 2002 Saturn LW200 Base 2.2L L4 - Gas
2003 there shows
89059802 , a diffr, sku!! shows fitments 03

2003 Oldsmobile Alero GL, GLS, GX 2.2L L4 - Gas 2003 Pontiac Grand Am SE, SE1 2.2L L4 - Gas 2003 Saturn L200 Base 2.2L L4 - Gas 2003 Saturn LW200 Base 2.2L L4 - Gas
that is the GM answer, others like engine builders/sellers
my say different even tell you what must be changed to do it

1 minutes work me. just reading at gm.com

check IAC located on throttle body


search for 2001 Saturn sc2 IAC

Check for a shorted or grounded fuel injector the test light will flash but there's not enough current to move the injector. Use a DVOM check that they're all the same.

Fix your car right away, by clicking the link
2002 SATURN SC2 REPAIR MANUAL

Here's your book info is below...
Most auto parts stores carry Haynes Manuals. You can order them from Haynes if needed. Or...often they are carried in your local library.

I have done Ford and Toyota clutches using these books. Clutch replacement is not hard, just time consuming...And easier if you have a lift.

Note: If like many vehicles, don't forget to replace the engine rear main seal while you have access with the fly wheel off.

You can call Haynes and ask specifically if the book covers the repair you are attempting. I have called them to get more specific wiring diagrams not always provided with the books. Very helpful in providing tech data... I have a Haynes manual for all my vehicles...makes maintenance and repair much easier than researching every I need to do something to my vehicles.

Best of luck finding the information you need...

Here's your book info.

Saturn S-series Haynes Repair Manual Online covering all 1991 thru 2002 models of Saturn SL, SL1, SL2, SC, SC1, SC2, SW1 and SW2
Part Number #E87010
Haynes Repair Manual Online for the Saturn S-series covering all 1991 thru 2002 models of Saturn SL, SL1, SL2, SC, SC1, SC2, SW1 and SW2 has clear instructions and hundreds of photographs to help you perform anything from simple maintenance to basic repairs. Whether you're a beginner or a pro, you can save big with Haynes!
Complete coverage for your 1991 thru 2002 Saturn S-series (SL, SL1, SL2, SC, SC1, SC2, SW1 or SW2):

--Routine Maintenance
--Tune-up procedures
--Engine repair
--Cooling and heating
--Air Conditioning
--Fuel and exhaust
--Emissions control
--Ignition
--Brakes
--Suspension and steering
--Electrical systems
--Wiring diagrams

This needs to go to a dealer for testing. there is no magic fix for this very difficult to diagnose fault.

get a repair manual, they are cheap on ebay. follow the instructions.

I believe those are electric pick up from the drive shaft or the rear end...Look for the wires that may have come loose/disconnected..good luck.

crank sensor located behind engine, cost at advanced auto 21.00 dollors.

Open the hood if it says efiohc or single cam on the valve cover then it is a sc1 if it says dohc or twin cam than it is an sc2