sc2 running at times on 3 cylinders

I was given a 1993 sc2 for my 17 year old son. My husband is a mechanic and has changed several things including EGR valve ,celonoid, coil packs, wires, plugs, oxygen sensor,etc. It was running OK but now gets bad gas mileage and at times runs on 3 cylinders. It has a new radiator as well......any thoughts?????????

coolant temperature sensor. that is the main cause to poor gas mileage on a saturn. it also causes poor drivability and sometimes causes the car to not start. if you replace it, replace the connector that goes with it because it has also been known to corrode and cause the issues. buy the sensor from the dealer!!!!! it is like $15 the connector im not sure, if you only replace the sensor and have same issues then its probably due to the connector. you should always replace both before saying that isnt the problem. if there is no dealer near you check out........ www.saturnparts.com or www.saturnparts.net

i think saturnparts.net is cheaper and is typically always cheaper then the dealer.

saturn parts.com is cheaper. the sensor is a 21025106 and the harness number is 12117087 for that sensor.

coolant temperature sensor. that is the main cause to poor gas mileage on a saturn. it also causes poor drivability and sometimes causes the car to not start. if you replace it, replace the connector that goes with it because it has also been known to corrode and cause the issues. buy the sensor from the dealer!!!!! it is like $15 the connector im not sure, if you only replace the sensor and have same issues then its probably due to the connector. you should always replace both before saying that isnt the problem. if there is no dealer near you check out........ www.saturnparts.com or www.saturnparts.net

i think saturnparts.net is cheaper and is typically always cheaper then the dealer.

We replaced that already. That was the first thing to replace after getting a new radiator............thank you though...........

we replaced that already, right after the new radiator...thank you though!!!!!!!!!!!

we replaced that already, right after the new radiator...thank you though!!!!!!!!!!!


ok but you did say it was running fine before hand right? also do you know where you got the sensor from? it can be replaced then a day or even longer it can foul out. ive been through 3 of them in 2 days till i decided to buy one from the dealer. if its 100% dealer replaced with connector piggy back too, then you need to look at wires and plugs. what kind of wires and plugs did you buy and what are the plugs gapped at?

i still say the coolant sensor may be new, but from the sounds of your issues its probably bad. do you have any diagnostic codes? if you have codes put them up and it will be easier.

I just had the intake gasket replaced on my '99. I had an occasional misfire because of it.
You can check the gasket by spraying some throttle body cleaner in the area of the gasket. The rpms will change if there is a leak. My leak was by #1 cylinder, the gasket was almost gone at #4 cylinder

I just had the intake gasket replaced on my '99. I had an occasional misfire because of it.
You can check the gasket by spraying some throttle body cleaner in the area of the gasket. The rpms will change if there is a leak. My leak was by #1 cylinder, the gasket was almost gone at #4 cylinder


im thinking that was a common problem on the sohc models. i havent headr much i dont think at all for dohc models.

how bout' checking out them Saturn Parts (http://www.satpartswholesale.com/) at http://www.satpartswholesale.com/

A failing ECTS could also cause your brakes to fail, turn signals to blink opposite of each other, halitosis, diarrhea and can also wreak havoc on your social life.


Seriously. Anybody thought of a failing fuel injector? Get a $15 mechanics stethoscope at Sears and listen to the fuel injectors.

A failing ECTS could also cause your brakes to fail, turn signals to blink opposite of each other, halitosis, diarrhea and can also wreak havoc on your social life.


Seriously. Anybody thought of a failing fuel injector? Get a $15 mechanics stethoscope at Sears and listen to the fuel injectors.

Or get a 1.00 screwdriver lol..

try the ignition modual mine did the samething the day after i bout it i replaced that and it ran fine