2.8L FI hard to start, runs great.....

[BiegeHansen]

My 2.8L FI v6 Cutlass Ciera Cruiser has had a problem for a few months. To start it, you have to crank it and crankit and crank it. If it does start, it runs great. I have been bypassing the problem for a few monthas now bu rotating the distributor cap to start the engine (it starts right up if it is advanced enough) and then I change it back to normal timing while it is running. I recently replaced the timing chain and I have replaced the MAF sensor. The computer keeps giving me the error for the MAF sensor but replacment does nothing. My timing is right but starting is just not easy. I have checked the fuel pressure, the fuel filter, I have even removed the air filter in an effort to get a better air/fuel mixture. The fuel seems to be very rich when it is burned, as if it is getting too much fuel or too little air. Could it be caused by a bad fuel injector, leaking fuel into the engine and flooding it? What can I check?