service engine soon !!

[87droptop]

HI ALL, MY 87 VETTE HAS SHOWED THE "SERVICE ENGINE SOON" LIGHT 4 A WHILE. LONG WHILE. IT RUNS VERY NICE, NO PROBS. A MECHANIC FRIEND OF MINE SAID IT WOULD BE THE OXYGEN SENSOR, DONT WORRY, AS LONG AS IT RUNS GOOD. NOW, IT RUNS VERY RICH, STILL GOES GOOD, BUT IT DRINKS A LOT MORE, AND I CAN SMELL IT THROUGH THE EXHAUST... ANY BODY HAVE ANY SUGGESTIONS IF IT COULD BE THE OXYGEN SENSOR OR SHOULD I BE LOOKING FOR ANYTHING ELSE ???  THANKS

[Thunder Kiss]

The "service engine soon" light could relate to a number of things.

When the light is displayed, a trouble code is stored in the cars ecm.  The code relates to the area that needs attention.

The first thing you need to do is retrieve the trouble code.  Instruction on how to do this can be found in this fact sheet.

Once you have the trouble code, you can see what it relates to in this more in depth article

Keep in mind the trouble code only points to the area that needs attention - it doesn't mean you have to replace that part.

[77CVT]

The error comes on for a reason - why trust a "mechanic" that gives you that advice?

You need to get the codes to pinpoint the error!  

O2 sensors don't last forever.  I replaced mine just to be sure after I rebuilt the engine.