i took out the spark plugs and they have black soot on them, this means the engine is running rich right? what are some common causes? it might be the opti, is there a way to check it with autotap? i have it but don't know how to use it very well yet. oh, the engine runs rough from idle to 1300 rpm, then it smooths out. i went through some water a while back and i know for sure the 02's got wet because there was a leak at the y-pipe of the FLP's. there is no SES light, and there are no DTC's stored in the computer. if any one can aid i sure would appreciate it, thanks .

andy

 

If its running rich enough to carbon up the plugs, its most likely a PCM problem, but can be related to virtually anything that causes a misfire.

You may have a condition where the PCM is getting false info about the A/F mixture....
-faulty O2 sensors
-exhaust leak before the O2 sensors
-misfires

The PCM responds by adding fuel you don't need, it runs rich.

OR....

Or, you may have a condition that is causing it to run rich, and the PCM has "bottomed" out the long term fuel corrections, and can't get it under control...
-excessive fuel pressure
-leak in fuel pressure regulator
-saturated EEC canister

One look at the long term fuel corrections (BLM's) will tell you which case you have. If they are way above 128, it is probably a "false lean", the first list above.... if they have bottomed out at 108, its something from the second list.