Chevrolet Repair: hard to start,ruff idle, chevrolet corsica, 1995 chevrolet corsica

Question
hey brian thanks for your time. i have a 1995 chevrolet corsica with a 2.2L with a auto trans.it has  167,000 miles.heres my problem i went to start it one morning and it would not start.so i pumped the hell out of the gas pedal and it barly started it blew a lot of black smoke at first but then it went away.the car ran fine for the rest of the day until the next morning and it did the same thing.this went on for about 3 days and each time it got wores.now when it starts up the motor shakes real bad at idle.but if i give it gas to around 2500 rpms or more the shaking goes away and it runs good at a high rpm. so i replaced the fuel filter,air filter and spark plugs.all 4 plugs had black ashy carbon on them.their has not been any warning lites or codes at all given.the car ran great before this and it even just passed the new jersey sniffer test.so if you have any ideas on what i can try next.

Answer
oil pump or the fuel pump, sound liek one  is relaly over doing its job, chek the oil levels and then  put fuel cleaner in gas. sounds like the engine get salot of gas and then starts thus igniting the gas alot of it and POOF black smoke.  and make sure the plugs are clean. aslo try some valve cleaner too. i bet that would help alot.