Hey, all. i have a 2000 sl1 with 145k miles that i inherited, and it's having a couple problems. (Check engine light and rough running). I was hoping someone with experience could help, because i'd hate to watch my car die from lack of knowledge for a second time.

here's the issues that i'm noticing.

-High idling. When i turn the car on it goes to 2000 and then to about 1200 and stays while slightly dancing. slightly. when i put it into drive the rpm goes to like 800. After it's warmed up and i put it in park, it likes to sit at 1.5. and it feels like it wants to go down, but doesnt...

-Rough shifting. I'm not sure if this is normal in older cars, but it just seems like it shifts aggressively. Let's say i'm going 50 and brake, it kind of jerks while downshifting like it can't stop itself.

-something else i've noticed that's happened rarely but is concerning is that when i back out of a parking spot and go into drive, sometimes it seems as if i do that too fast, the car will just go into neutral and stay in neutral until i put it in park or turn it on. other times i switch from park to reverse and it shifts really hard and loudly.


honestly that's all i really notice. there's this knocking noise but i dont think it's the pistons, it's too slow.

I've reset and pulled my codes, here's what i have:
-P0446 EVAP Vent System Performance
-P0301 Cylinder 1 Misfire Detected
-P0507 IAC System too high
-P0708 Transaxle Switch Circut High Input
-Pending- EVAP again

. I took it into meineke and they reccomended replacing the throttle body but they "can't do it anymore because the part is hard to find". Then, someone else told me that there's no way it's the throttle body. I did find a throttle body on ebay though, so that's an option if people think that's the case,

I appreciate any responses. Is it possible to get no check engine light on a 25 year old car or is that a myth?

-Kyle

 

A leaking intake gasket is very common on the SOHC for that year. You can confirm it by spraying something like brake cleaner at the intake to head joint and see if the rpm changes.

 

Cylinder one misfire is likely because the intake manifold gasket material around cylinder number one has gotten partially sucked into the intake path. This also serves to make a vacuum leak at that cylinder. This will increase your base idle.

Clean the throttle body pain special attention to the IAT. See if that activity improves throttle response and gets rid of the IAT code.

Transmission issues you described are part and parcel Saturn S series automatic transmission issues. Banging into reverse is referred to as reverse slam around here. The input shaft nut has worked its way loose and backed off from where it should be. You should really replace it with a new one but most people just tighten it up. With the car sitting in neutral when it shouldn't be, that sounds like it may be a solenoid tissue or a line pressure issue or both. There should be enough line pressure to shift gears with the shifter upon demand. Leave you also have a transmission code that I can't see it right now. Probably part of the problem.

As for the evap code, again I need to look at the number and look it up. I'll be back.

 

P0508 is for a problem with your neutral safety switch and possibly the shifter range switch. Basically, the sensor vent the text would gear you are in on the shifter is not sending correct information to the PCM. This would certainly explain why the car doesn't shift when you tell it to. It doesn't know what gear it is in.
P0446, evap, check to make sure your gas cap is tight and seal around the gas cap is intact.