Car starts and blows black smoke and use a lot f gas and want idle.

Diesel or gas

Black smoke is a sign of carbon and incomplete combustion. Too much gas is getting inside and constipating your engine.

If it is idling ok, then the anomaly is somewhere in the main jet metering system responsible for excessive gas going to combustion chamber.

there is a very common issue with bad distributors in nissan pathfinders,xterras.and quest. just replace the distributor

A bad coolant temp sensor for the ECM will cause that problem ... they are cheap and easy to replace. One other possibility is a piece of carbon stuck in the EGR causing an internal vacuum leak ..
Good luck.

Black smoke tells me your piston rings are worn. Also the fumes you have explained tells me the valve seals are worn and leaking oil as well
The leaking valve seals and pistion rings will expell the fumes out through the exhaust. If you check your oil level every 50 miles and the oil level is down a half quart or more serious engine wear has occured and needs to be rebuilt soon

It could be the cold start valve is staying on. I would also check the thermo-time switch. Check the cold start valve for power after the car is warmed up.

coolant temperature sensor boken, check and replace if defective.

the black smoke means that it is buring the gas to rich.

MASS AIRFLOW SENSOR THERE ABOUT £6O WHEN THEY PLAY UP THE CAR WONT IDLE PROPERLY AND POOR RUNNING/HESITATES BEFORE IT PICKS UP AGAIN, NOT SURE ON THE BLACK SMOKE THOUGH, GOOD LUCK .