Not starting like it used to.

[andy]

Over the last few months I've noticed that my car doesn't fire up as quickly as it used to. Before, I would turn the key after the glow light went out and the engine would fire up before the engine completely turned over. Fast! Now the engine starts up after a couple of seconds of cranking(maybe 2-3 turns of the engine). The engine runs great. Really smooth, doesn't burn any oil... I have run bio-diesel a few times and I have replaced both filters. I'm not sure, but I think my fuel economy has gone down a bit also. Any ideas? andy