Hi all, my saturn started flashing the service engine soon light today on my way to work. The power was reduced greatly and the engine had a visible shake when I got stopped.

I changed the sparkplugs because they were horrible and I thought that would fix my problem as some of the electrodes seemed to be completely burned up. The car only has 45,000 miles on it. The sparkplugs heloed for about 30 seconds and then it went right back to the rough idle.

The rear smells like something burning and the exhaust is extremely hot. I know there are so many things it could be such as clogged cat, bad injectors, head gasket, ignition module, coil packs, or other things. I don't want to just throw money at parts because that gets expensive. I would like to know if you all can help me out with where to start to begin actually diagnosing the issue.

I have access to most tools and feel like I'm a slightly above average diy mechanic so any suggestions you all might have are greatly appreciated.

 

Please post all codes pulled from the diagnostic port.

Use a true scanner which will access the body control module codes as well as transmission, communications, and other codes.

Alternatively, go to AutoZone or similar and get some of the codes read for free. These will be only the P codes but will give us a start.

 

P0300 is random misfire. Is the check engine light flashing or on solid? Might just need a coil pack if the plugs were truly worn out. Check compression before purchasing more parts.

 

The light is solid unless I start to drive and then it flashes. I will do a compression test today and post the results.

The only code is the P0300. All modules came back good except my SDM which my scanner can't communicate with due to a separate issue.

 

The compression test results were:
117
118
122
120

I'm leaning towards an ignition coil or the ignition control module. Is there any way to test these components?

 

I have only had the coil pack fail on these engines. Usually fails to fire #4 plug. This failure is caused by running plugs to many miles.

 

I just wanted to follow up and say thank you. New coil and ignition module installed and everything is well again. Well except my blower which niw works on all settings except the front vents but the issues aren't related I don't believe.

Thanks again.

 

You’re welcome, the dash vent problem is probably dry linkage on the passenger end of the hvac box. If your VUE is anything like my L series cars the mode motor runs some complicated linkage to shift the mode doors with one 45 degree rotation of the motor. With defrost and dash as the extremes the motor has to push some fairly complicated plastic arms and cams to make it all work. Now that these are 20 years old some lube on the linkages really helps.