Nissan gear ratios

Fig. Cylinder head bolt loosening sequence - Altima & Maxima 3.5L engine

Install the cylinder head bolts and torque in sequence as follows:

1. Step 1: 72 ft. lbs. (98 Nm).
   
2. Step 2: Completely loosen all bolts.
   
3. Step 3: 26-32 ft. lbs. (34-44 Nm).
   
4. Step 4: plus 90-95 degrees clockwise.
   
5. Step 5: plus 90-95 degrees clockwise.

Fig. Right cylinder head bolt torque sequence- Altima & Maxima 3.5L engine




Fig. Left cylinder head bolt torque sequence- Altima & Maxima 3.5L engine

Hope this helps; also keep in mind that your feedback is important and I`ll appreciate your time and consideration if you leave some testimonial comment about this answer.

U1000 - CAN Communication Line Signal Malfunction

Causes:
- Harness or connectors (CAN communication line is open or shorted)
- Faulty Engine Control Module (ECM)

Solutions:
- Poor harness ground connection

There is a service bulletin for the following Nissan models with U1000 code:

2002-2006 Nissan Maxima
2004-2006 Nissan Titan
2004-2006 Nissan Armada
2002-2006 Nissan Sentra
2005-2006 Nissan Frontier
2002-2006 Nissan Altima
2005-2006 Nissan Xterra
2005-2006 Nissan Pathfinder
2004-2006 Nissan Quest
2003-2006 Nissan 350Z
2003-2006 Nissan Murano

The service bulletin suggest cleaning engine and body harness ground connection to repair problem.

After 2002 Altima offers two types of engine: the new 4 cylinder 2.5 L QR model engine which is fairly powerful (175 horsepower) and, I believe, one of the best engine in its class the 3.5L V6 VQ model engine with 240 horsepower. The same V6 model as in in the Nissan Maxima, Pathfinder and Murano.
Both engines feature continuously variable valve timing using a silent chain instead of timing belt. Throttle cable is gone - the throttle operates electronically by wire based on gas pedal sensor readings. This design provides smoother transmission shifting and lower emission.
The 2007 Nissan Altima 3.5L Sedan, has a Timing Chain, and an Ignition Coil Pack. NO DISTRIBUTOR.