The 2005 NASCAR Nextel Cup Series began on Saturday, February 12. The ten race Chase for the Nextel Cup started with the Sylvania 300 on Sunday, September 18, and ended on Sunday, November 20, with the Ford 400.
Tony Stewart was the dominant driver going into the ten race "playoff" with five wins. Going into the final race before the Chase for the Cup, Stewart had amassed a 209 point lead over his nearest competitor, Greg Biffle. Points are reset going into the Chase for the cup, and Stewart’s lead was dropped to a 5 point margin. Leading into the final race before the Chase, ten racers were still mathematically contending for the final four spots in the Chase and only one point separated Jamie McMurray in 10th from Ryan Newman in 11th. In the end, the ten racers who qualified for the Chase for the Cup were:

1. Tony Stewart (3716)
2. Greg Biffle (−185)
3. Rusty Wallace (−304)
4. Jimmie Johnson (−316)
5. Kurt Busch (−412)
6. Mark Martin (−443)
7. Jeremy Mayfield (−488)
8. Carl Edwards (−602)
9. Matt Kenseth (−602)
10. Ryan Newman (−661)

Overall, Roush Racing was the dominant team going into the Chase for the Cup with five of the ten final racers from their organization (Biffle, Busch, Martin, Edwards and Kenseth).
This was the first season since his rookie season that Jeff Gordon did not finish in the top 10 in points.
The 2005 season was the first year of competition for the Dodge Charger, which replaced the Dodge Intrepid, a model that Dodge dropped from its consumer lineup for the 2005 model year. The change did little to improve Dodge's fortunes as a distant third manufacturer in NASCAR Nextel Cup behind Ford and Chevrolet. In 2004, Dodge won 4 of 36 cup races with the Intrepid. In 2005, the Charger won three races. The Charger was, however, much more of a success in the Busch Series, winning 10 of 32.
The 2005 season was the final year for the Ford Taurus, which was replaced by the Ford Fusion in the 2006 season. In addition, two prominent drivers announced that this would be their final season in NASCAR: Mark Martin and Rusty Wallace. However, Martin returned for 2006 and ran a limited schedule in 2007 and 2008, drove full-time Hendrick Motorsports between 2009 and 2011 and then part-time again before retiring at the end of the 2013 season. Also Ricky Rudd took a break after the 2005 season but returned by the 2007 Season.
One of the biggest controversies prior to the start of the season involved the elimination of two races – Darlington and North Carolina Speedway in Rockingham. The eliminated Rockingham race ends NASCAR's 38-year association with Rockingham. The races were replaced by new races at Texas and Phoenix. NASCAR also began moving start times later in the day starting this season; by 2007 the Daytona 500 finished in primetime.
Also, NASCAR announced in January 2005 that the owners of the teams in the top 35 of the previous year's standings would be guaranteed a starting spot in each of the first five races of the season. This further complicated the unique qualifying procedure for the Daytona 500, and severely affected the chances of some teams to make races after having a poor 2004. After the fifth race, the guaranteed starters were based on the current season's points, with changes possible from race to race depending on results.
The number of cars entered for each race was up slightly from the previous year. The Daytona 500 saw a dramatic increase in its car count from 45 to 56. The increase was in part attributable to a new NASCAR rule that allowed hard liquor brands to become sponsors on its race cars. Roush Racing (Crown Royal), Richard Childress Racing (Jack Daniels), and Robby Gordon Motorsports (Jim Beam) were the first to sign such deals.
At the end of the 2005 season, Chevrolet won the NASCAR Manufacturers' Championship after winning 17 events and garnering 259 points over second place Ford who captured 16 victories and 146 points. Taken from http://en.wikipedia.org/wiki/2005_NASCAR_Nextel_Cup_Series.

Race Results

Date	Site	Cars	Winner(s)	St	Make / Model	Miles	Pole	Cau	Laps	Speed	LC	Time of Race
2/20/2005	Daytona	43	Jeff Gordon	15	Chevrolet	508	188.312	11	45	135.173	22	3:45
2/27/2005	Fontana	43	Greg Biffle	5	Ford	500	188.245	7	40	139.697	26	3:34
3/13/2005	Las Vegas	43	Jimmie Johnson	9	Chevrolet	401	173.745	10	46	121.038	25	3:18
3/20/2005	Atlanta	43	Carl Edwards	4	Ford	501	194.69	8	40	143.478	27	3:29
4/3/2005	Bristol	43	Kevin Harvick	13	Chevrolet	267	127.733	14	115	77.496	14	3:26
4/10/2005	Martinsville	43	Jeff Gordon	16	Chevrolet	263	96.671	16	91	72.099	17	3:38
4/17/2005	Fort Worth	43	Greg Biffle	5	Ford	501	192.582	11	56	130.055	25	3:51
4/23/2005	Phoenix	43	Kurt Busch	2	Ford	312	133.675	9	43	102.707	16	3:02
5/1/2005	Talladega	43	Jeff Gordon	2	Chevrolet	516	189.804	8	30	146.904	33	3:30
5/7/2005	Darlington	43	Greg Biffle	3	Ford	505	170.024	12	48	123.031	30	4:06
5/14/2005	Richmond	43	Kasey Kahne	1	Dodge	300	129.964	9	53	100.316	21	2:59
5/29/2005	Charlotte	43	Jimmie Johnson	5	Chevrolet	600	192.988	22	103	114.698	37	5:13
6/5/2005	Dover	43	Greg Biffle	2	Ford	400		7	33	122.626	9	3:15
6/12/2005	Pocono	43	Carl Edwards	29	Ford	503	169.052	8	32	129.177	14	3:53
6/19/2005	Michigan	43	Greg Biffle	25	Ford	400	194.232	4	23	150.596	20	2:39
6/26/2005	Sonoma	43	Tony Stewart	7	Chevrolet	219	94.325	8	18	72.845	7	3:00
7/2/2005	Daytona	43	Tony Stewart	1	Chevrolet	400	185.582	9	41	131.016	7	3:03
7/10/2005	Chicago	43	Dale Earnhardt, Jr.	25	Chevrolet	401	188.147	10	47	127.638	17	3:08
7/17/2005	Loudon	43	Tony Stewart	13	Chevrolet	317	130.327	10	49	102.608	14	3:05
7/24/2005	Pocono	43	Kurt Busch	2	Ford	508	168.76	13	40	125.283	13	4:03
8/7/2005	Indianapolis	43	Tony Stewart	22	Chevrolet	400	184.117	10	43	118.782	15	3:22
8/14/2005	Watkins Glen	43	Tony Stewart	1	Chevrolet	225		7	14	86.804	9	2:35
8/21/2005	Michigan	43	Jeremy Mayfield	11	Dodge	400	191.53	7	30	141.551	19	2:49
8/27/2005	Bristol	43	Matt Kenseth	1	Ford	267	127.3	16	88	84.678	17	3:08
9/4/2005	Fontana	43	Kyle Busch	25	Chevrolet	508	185.061	11	43	136.356	30	3:43
9/10/2005	Richmond	43	Kurt Busch	5	Ford	300	128.425	12	60	98.567	23	3:02
9/18/2005	Loudon	43	Ryan Newman	13	Dodge	317	131.143	10	60	95.891	18	3:18
9/25/2005	Dover	43	Jimmie Johnson	5	Chevrolet	404	158.103	11	50	115.054	15	3:30
10/2/2005	Talladega	43	Dale Jarrett	2	Ford	505	189.26	10	33	143.818	50	3:30
10/9/2005	Kansas	43	Mark Martin	19	Ford	401	180.856	7	28	137.774	16	2:54
10/15/2005	Charlotte	43	Jimmie Johnson	3	Chevrolet	504	193.216	15	84	120.334	35	4:11
10/23/2005	Martinsville	43	Jeff Gordon	15	Chevrolet	263	98.084	19	113	69.695	15	3:46
10/30/2005	Atlanta	43	Carl Edwards	2	Ford	501	193.928	9	39	146.834	27	3:24
11/6/2005	Fort Worth	43	Carl Edwards	30	Ford	501	192.947	6	27	151.055	23	3:19
11/13/2005	Phoenix	43	Kyle Busch	15	Chevrolet	312	134.173	9	44	102.641	10	3:02
11/20/2005	Homestead	43	Greg Biffle	7	Ford	401	176.051	8	37	131.431	21	3:02