2001 Nissan Sentra Starting problems

[Mysfyt]

I have a 2001 nissan sentra and I'm having a starting problem. Last wednesday, the car would not start. The best way for me to describe it is that the engine is turning over but not starting. I don't hear any clicking noises. The car sounds and act like it's going to start but nothing (kinda like the engine is turning over and over). When I first had this problem starting about 2 weeks ago, when the car wouldn't start, after I'd let it sit for about 5 to 30 minutes (it varies), the car would start. But it's getting worse, now the car is rarely starting for me. So, last wednesday, I had it towed to a mechanic and he recieved the car at the end of the business day so it sat overnight. the next morning, for him, the car cranked fine. He kept it for a few days (over the weekend and he doesn't work on the weekends) and monday morning, for him, the car cranked fine. so I decided to go ahead and replace the battery (it was 3 years old) and the altanator belt because it looked a little worn out. He also cleaned my battery connections and soldered a point on the cable that he stated as being "loose" (perhaps causing a bad connection). After paying, I started the car and it hesitated for about 3 seconds but It DID start. Once the car is running, it runs absolutely great. So....I came home and it sat from about 4 pm to about midnight (it's kinda cold here in memphis, it sat in probably 50 to 40 degree weather during this time), I went out just to see if it would crank and to my fear, the car won't crank. It just acts like it's gonna crank (no clicking noises, just kinda chugs).

All help is appreciated in advance
Modified by Mysfyt at 3:25 AM 12/8/2009