High Idle in Neutral

[MtBik49833]

Hey everyone, this is my firt post with the site. I have a 2001 Saturn SL with a manual transmission. Lately it has been idling really high (sometimes as high as 3000 rpms) when I have the car in neutral. It has been somewhat cold out lately but it does it when the car is warm as well. I have also noticed a severe nosedive in my gas milage. I have been reading a bit and it sounds like maybe it is the engine coolant temperature sensor? Any ideas/suggestions? Thanks.

[99saturnspeed]

Originally Posted by MtBik49833

Hey everyone, this is my firt post with the site. I have a 2001 Saturn SL with a manual transmission. Lately it has been idling really high (sometimes as high as 3000 rpms) when I have the car in neutral. It has been somewhat cold out lately but it does it when the car is warm as well. I have also noticed a severe nosedive in my gas milage. I have been reading a bit and it sounds like maybe it is the engine coolant temperature sensor? Any ideas/suggestions? Thanks.

I have a 99 sc2 and was having a simalar problem. It was the 02 sensor behind the cat. That 02 sensor has a heater circuit in it and sometimes they go bad. Mine was due to my excesive 150 shot nitrous.

[peppermrj]

Originally Posted by MtBik49833

Hey everyone, this is my firt post with the site. I have a 2001 Saturn SL with a manual transmission. Lately it has been idling really high (sometimes as high as 3000 rpms) when I have the car in neutral. It has been somewhat cold out lately but it does it when the car is warm as well. I have also noticed a severe nosedive in my gas milage. I have been reading a bit and it sounds like maybe it is the engine coolant temperature sensor? Any ideas/suggestions? Thanks.

The first sign is bad gas mileage with an ECTS. I'm not sure when the factory went to the newer brass tipped sensor. 2001, 2002. But it is real easy to check. Pull off the wire connector (inspect it while it's off) and simply unsrew the ECTS (10mm I think). If it is the composite/plastic material pitch it and replace with the newer brass tip OEM. If it is brass replace it with a sealer of some type (Teflon tape). Be sure not to over tighten. they will break if you try to spin them in till they won't turn.

I got mine from saturnparts.com or was it .net, either one has them for about $10.00 + shipping. If you need anything else get it at the same time if you mailorder. Shipping and handling isn't cheap. $7.00 or $8.00.
Let us know how U do and good luck.

[peppermrj]

I should also ask if it does it all the time?
You should also do a quick visual inspection of the gas pedal (make sure nothing is interfering with the linkage/cable under the dash), The linkage/cable under the hood (from the firewall to the throttle body) and the throttle plate itself(check that it is returning all the way inside and out). I had a pcv filter get sucked up into the butterfly and it would not let it return on an old ford years ago. I'm glad it just got stuck there and not sucked into the motor.