Hi! I have a 92 2500 van with the 5.7 in it. The van has been running fine untill recently. I went to start it and it woulden't start (although i had just drove it 20 minutes prior). I noticed a bit of black smoke coming out the exhaust. I left it alone for about an hr and tried it again and it fired right up but when you hit the gas a bit of black smoke came out. The van had been sitting for about a yr or so,