: help on my 99' seville sls

11-18-07, 12:53 PM
Im 18 and I have a 99 seville sls and my engine light keep turnin on and I dont to sound ignorant. I took it to autozone so they can check whats wrong with it and it said that the coolant temp is always low, cylinder misfire dected random cylinders, all 3 of the o2 sensors have somekind of malfunction in heater circuit, and cylinder 8 Ignition circuit open. Im not sure what to do but my uncle told me just to change the o2 sensor and if thats it what brand do I use. The engine has a little over 150k miles and I always do maintance but im not sure why all this happen. If someone can PLEASE PLEASE help me out I really need it.

11-18-07, 12:58 PM
pull your own codes
do a search to find out how
and sounds like HG with random misfires as well as coolant low

11-18-07, 01:01 PM
Do a cylinder compression test and it will tell you the truth .Another thing, if you smell some burnt coolant out of exhausts it's another symptom of HG

11-18-07, 02:12 PM
how do you pull your own codes??? and whats HG???

11-18-07, 03:52 PM
HG = headgasket
As for the pulling codes :
Turn ignition "ON." Engine can be either OFF or RUNNING.
Depress the "ON/OFF" button and the "UP ARROW" end of the info
button on the driver information center simultaneously for a few
All the dashboard lights will illuminate, including the segments of
the DIC display. You are then presented with text.

You can cycle through different questions using the UP and DOWN
arrows on the info button.

11-18-07, 11:02 PM
See post #2 in the sticky in the Tech Tips section for more info.