2000 SL-1 fast idle problem during cold weather only

You need to check and/or replace the thermostat and/or the temp. sensor. Take a meat thermometer and stick it in the overflow tank. The temp gauge on the dash should register above the 1/4 mark after at least 15 minutes of driving. If so, the meat thermometer should read above 180 degrees. If the meat thermometer reads 180 but the gauge isn't above 1/4, then you need to replace the sensor. If the meat thermometer doesn't read 180 or higher, then you need to replace the thermostat. The thermostat in these cars, though it doesn't fail on its own, has an unnecessary rubber gasket that fails, and allows coolant to leak past even when shut, causing the engine to not warm up thoroughly. IF the engine doesn't warm up, the idle won't come down--speaking from personal experience. I had to replace both items on my car. Now it idles fine, and after a bit of driving the gauge registers between 1/4 and 1/2, but always above 1/4. DO NOT tamper with idle adjustments unless you have exhausted all other possibilities. They are factory set, critical, and almost never need readjusting. Good luck.

I had the same problem. I took it in to a station, my EGR valve was plugged, the passages were plugged also causing the pvc valve to fail and a clogged air filter. They cleaned the throttle body and were able to clean the egr valve installed a new pvc valve and air filter. I can happily say that the car is running smoothly. I no longer have the RPM spikes and when I come to a stop the car idles around 900 rpm's.

If problem persists replace the ECT sensor (Engine Coolant Temperature). Saturns have been known to have problems with them especially in earlier models.

Original problem..."
Mar 03, 2009 - Same problem just on a 2002 sl model Saturn... Please see link to see what I have tried, no solution yet. I can take this car out and drive it to warm up, stop at a stop sign and with clutch pushed in the car runs at 2000 rpm. shut the key off, I here what sounds like fuel pump run for a couple seconds, then a clicking sound from in the dash or under the hood...car is off. then restart the car and idles at 750 rpm nice and smooth. but on the highway driving 65 mph it intermittently chugs, I will just take my foot off the gas, it stops chugging, put my foot back in the gas and it will run fine until it will do it again. Sometimes I can go 15 miles before it will happen again, other times it will be like 15 seconds. (I am beginning to think it is possessed!) LOL!"
My 2002 Saturn SL... I tried everything, however the chugging was stopped by taking the Electronic EGR Valve off and Thoroughly Cleaning it with Carb Cleaner.. Letting it dry out and putting it back in, the car runs like a sewing machine... BTW that is a $150.00 item at Autozone!!! I was like no way am I buying a new one.. It was stopped up on the inside with carbon buildup bad.. but cleaning it did the trick!!! Just thought I would post what I did to resolve my problem. Thanks everyone, and sorry I haven't posted before now.

TRY TAKING BREATHER HOSE OFF AND SPRAYING CHOKE W/ CARB CLEANER. IT MAY BE DDIRTY. DO A DIAGNOSTIC ON IT IT MAY BE A IDLE SENSOR GOING BAD?

Only a couple of things can cause this problem

1) You have bad o-rings around the injectors. 18.95 for all injectors and about 1 hrs work
2) you have a bad intake manifold gasket. 20 bucks and about 3 hrs. (test by spraying some carb cleaner around the manifold while it is running. If it begins to stutter, that's the problem)
3) control valve problem. 80 bucks and about 15 min. Take off the air intake hose and see if the butterfly valve is open or closed. If it's closed all the way and you still have problems go back to items 1 and 2.
Good luck!
Dan Ryant

EXACT SAME PROBLEM with my 2000 Saturn SL w/SOHC engine!

Short answer: Change the TPS(Throttle Position Sensor), it's less than $40, you can do it yourself in less than 10 minutes. It would take 30 seconds, but the screws are a bit difficult to reach. Mine took a Torx #15 bit.
Long answer: Here's the part that nearly everyone is ignoring, the idle resets to normal after re-starting the engine. That fact alone is a HUGE clue, it means that it is NOT something constant, like a ruptured intake manifold gasket, but something variable and electronic that gets "re-set" on engine restart. Huge clue #2 is that this problem does NOT generate an error code that triggers the "check engine" or MIL lamp; at least not in my case. This means that the system "thinks" it's acting as it should. This tells us that the computer is getting faulty data, and the worse part is, it doesn't even know it! Where do we get data? SENSORS!!! This led me to rule out the IAC( idle air control motor). If the IAC were being commanded to set the idle to a certain speed, and had failed, that would have resulted in an error code. Since the problem seems to occur upon exposure to cold air(even when car is fully warm), my first guess was the air temperature sensor(also called the Air Charge sensor). Since it was only $11, I changed it. Sadly, no luck, the problem persisted. Next, I changed the TPS(throttle position sensor). The idle is now completely normal, regardless of the weather. Also, the car seems to run soother as well. Apparently, the bad TPS was telling the computer that the throttle was open, so the computer would command the IAC motor to open and allow more air in, this boosted the idle speed to 2 to 3 times normal. The computer didn't mind, because it "thought" that the throttle was open, so the increased engine RPM was normal. Anyhow, that's my theory, the important part is that a new TPS seems to have done the trick. Good luck, work safely, happy driving.Robert M2000 Saturn SL199,050 miles as of 4/12/2012

This car does need to have the thermostat working properly...Also make sure that the temp sensor is working.........Have seen this before......Make sure the thermostat starts to open between 182 to 190...Its fully open at 212...........If egr is ok...no codes are present....and the rest of the sensors check out you should be ok...On another note, i have found these car to give very little problems untill the 125k mark,after that, they seem to have little problems that can be costly if not diagnosed properly......

I have a 2000 saturn sl and none of the gauges work.Car starts fine headlight work yet the hazards don't. Is there a fuse or relay I need to change? If so where is it located?