Hello I just got a Saturn passed down to me and was running fine for about 40 mins when I lost power and the engine light came on and started flashing. I got the codes p0300 and p0340 for random misfire and camshaft position sensor. I replaced the spark plug wires and plugs and nothing seemed to change so I decide to change out the crank shaft position sensor which made the car run rougher. I know it needs to go through the relearn process which I tried by holding it at 3,500 rpms for a while but that didn't work either. I'm now stuck because I know the car wont relearn the sensor until the misfire is fixed. The car has 122,xxx miles and was sitting for about a year with a full tank of gas so maybe the misfire is related to that but I don't know, any suggestions?

 

I'm thinking bad gas.
Bad gas causing misfires, misfires random. Misfires can trigger p0340 since they look funky to the ignition system.

To a loaner tool for a fuel pressure gauge from AutoZone or similar. It's free. Measure the fuel pressure at the Schrader valve on the fuel line under the hood with key on engine off and key on engine on. Report the values here.

Also,
Pull the plugs, take a picture, and post.
Go out and buy two sets of stock NGK plugs for the dohc 2000.
Install one set of plugs, reattach everything, and try again.

Pull those plugs, take a picture, and post.

 

Is the mechanical timing good. Chain?

 

I thought about that first, but the chains on the S car engines tend to break rather than slip. Usually from oil starvation. I've been told it will run one tooth off without smashing the valves. Pretty low mileage for chain issues, but again we do not know it's history.

Per Gary, put everything I mentioned on the back burner, pull the plugs, and do a conversion test.

How much oil does it burn per 3000 miles?

 

I'm confused. You state that one of the codes indicates the cam position sensor but you replaced the crank sensor. Why would you replace the crank sensor instead of the cam sensor? Makes no sense to me. I'm out.

 

I inspected it further and tested the ignition coils. One did not have spark so I replaced both to be safe and runs perfectly now

 

Wild.
That's not how Saturn ignition coils on the S cars usually die.
Also, if there was no spark whatsoever on one and four or two and three, I'm surprised that wouldn't have been detected as two different cylinder specific misfires. Would definitely explain the p0340 the for the ignition system.

Well good work I'm glad you are back up and running.

 

I had the exact same issue with an Ion that sat up for six months. It had 175k on it when I bought it. I disconnected the fuel line, drained the tank, put in some new gas and a can of seafoam (not recommending it, just telling you what I did in desperation to get the car to run), and cranked it. It ran really rough for about five or ten minutes, and then slowly cleared up. I drove it for a week to work and back, then replaced the fuel filter just for paranoia. The car ran great for a few years until a person on substances ran a red light and t-boned me. Hated to lose that car.