hi all um im just curious to know what would cause the car to run rich as i just had the spark plugs replaced and at 30 dollars each i hope they last.
well the other plugs were black as and i think im having tell tale signs of the car running rich??
what are the usuall things that go on these engines that may cause this

Okay, more info needed - What are you driving, engine, fuel you use, any mods like aftermarket filters....

The reason is too much fuel or not enough air or both.

ok sorry
well i have a 6G72 GDI v6 1997 diamante
i think the problem is i have to much fuel going into the car as the plugs were black as hell.
just replaced them and i did a run and god extreamly good consumption. i am not running any mods or anything andi use 96 octane fuel.
it runs ok but when u do put ur foot down to fat it it sometimes dies but usually it makes a splattering sound and has a dead spot then it goes ok. is this normal for these engines

what part of the plug was black? the tip and insulator should be browish/whiteish/tan colour. if the base of the plug is black thats fine. if you want to know if it really is running rich, then check the ECU diagnostic codes, or hook up a simple meter which can check (jaycar sell kits ~$14) in parallel to your sensor in your exhaust manifold. this sensor does all the work by sending information to your ecu to maintain a perfect ratio. it checks how much oxygen is in your exhaust and sends a voltage reading (lean or rich). the sensor works only when the car has warmed up - it is normal for it to run rich for like a min or so. if you have the jaycar meter you will see the leds go left to right constantly which indicates "closed loop mode" which means its running properly.

if not grab a multimeter which can measure mA and watch it fluctuate. i HIGHLY doubt its this as its a fairly new car. really with ECU controlled cars it running rich is unlikely - poorly yes due to other stuff not being maintained or looked after.