I have a 94 STS, which has most definately NOT been meticulously maintained.

The service engine message has been on for about 20k. I haven't paid any attention to it because 1) The car had 110k on it when it came on, B) It still ran fine, and Last) the car owes me nothing, and I figured when it stopped running/seized, I was done with it.

Well, the engine leaks oil, which from reading here is somewhat normal. It also smokes after driving, although that's been somewhat intermittent.

So I read the thread about WOT for cleaning the engine. I gave that a try, and also switched to Chevron V 94 octane on the last fill up.

So far, the engine has stopped smoking, I've picked up 1mpg, and the service engine light has gone out. While I expected some better gas mileage, and I hoped for less oil smell, I'm stumped by the engine message disappearing.

Any thoughts of a non- personal nature would be appreciated. :tisk:

I would access the obd system to see what codes are set(if you haven't done that already). It may have been an intermittent problem that may have cleared itself up by your implementing WOT. But I would still check the obd to narrow down the issue with the light.

I would access the obd system to see what codes are set(if you haven't done that already). It may have been an intermittent problem that may have cleared itself up by your implementing WOT. But I would still check the obd to narrow down the issue with the light.

Does the obd system store the data, even if the problem has cleared up?

Yes, it will show up as a code but will have history displayed after it.

Yes, it will show up as a code but will have history displayed after it.

:thumbsup:

Many thanks, a job for tomorrow night.

Does the obd system store the data, even if the problem has cleared up?
I believe it stores the code as history for 50 ignition cycles after which they will be cleared if they don't reoccure or are cleared manually.

I've got to get me some of that gasoline! :rofl:

Yep, check the onboard diagnostics by simultaneously depressing and holding the OFF and WARMER buttons on the climate control until the diagnostics activates and the codes will display. Any old codes should still be stored as history if it was within 50 ignition cycles.

If it was something like an O2 sensor not ready it could clean up with some WOT as the extra heat would clean any deposits off the sensor...but...the diagnostics should give a clue.