I have a 1999 saturn sl2 dohc with over 160,000 miles. Last week when i started the car in the morning the engine reved real high over 3000 and then shut off. It would crank and start but run rough when the idle came down then shut off immediately.
I replaced the coolant thermostat sensor, fuel pump relay, spark plugs, pcv, and took apart the throttle body cleaned it to near brand new and replace the throttle body gasket. Right after that the car started idles and ran like new. I let it sit over night and when i went to start the car it wont start now. It just cranks but never starts at all. Any ideas? I am at my wits end. I have no ability to read codes or get it to a repair shop and i am not a mechanic.

 

You need to check for the basics first. Pull a spark plug out and ground it and then crank the car to see if it's getting spark. If so, make sure you're getting gas to the throttle body. If you've got spark and fuel, then you need to check for compression. You have to have all 3 of those along with air to the tb in order for it to run. You may have a defective electronic coolant temp sensor. The ECTS is a notorious problem area for the Saturns and should be replace with a genuine GM part along with the plug harness, not some aftermarket junk.

 

Thank you. I will check those things out right now and get back to you.