Check engine light came on. Obd2 code was P0303 and intermittently code P0300 indicating cylinder #3 and multiple cylinder misfiring. Took the car to local garage. Installed new spark plugs and with Nissan guidance, they performed upper intake cleaning. Check engine light came back on for same codes. Notified Nissan and brought car to dealer as advised. Dealer replaced coil pack #3 and performed fuel induction cleaning. Cel came back up and dealer recommended removal of head to inspect for warpage after already spending $1200 on this issue. Nissan said they couldn't let me know if any or no financial assistance on the issue until I pay another $600 to inspect the head when a compression test should have been performed when Nissan first worked on the vehicle. Overall, not satisfied with Nissan for dropping the ball on an obvious recall under service bulletin ntb-10-056.

- Hopewell Junction, NY, USA

A carbon buildup in the cylinder head causes the vehicle to shake and during initial start up and stutter/shake during acceleration. This build up is due to a design flaw in the cylinder head. It cause multiple unsafe instances when trying to merge with oncoming traffic and safely navigate in normal driving conditions. This is a know issue to Nissan and they have redesigned the head but are unwilling to help with the issue. This occurred on our vehicle with only 35,000 miles on it.

- East Amherst, NY, USA

Check engine light came on. Diagnostic error code was P0300 indicating intermittent multiple cylinder misfiring. Took the car to the dealer. Was informed that this is a known problem with Altima hybrids due to carbonation of the engine due to frequent starts and stops. Nissan has redesigned the cylinder head and at one time considered a recall but then decided against it and are handling it on a case by case basis. Initiated contact with Nissan corporation. Nissan responded back in 10 days that they will not cover it because the car is not under warranty anymore (warranty expired at 60,000 miles). Newly designed cylinder head was going to cost $2700. Decided to decarbonize the car engine using a kit. Car has been running fine since then. Cost $185. Bottom line: Nissan should have covered the repair cost because it was caused by a design flaw in the cylinder head. Nissan should have advised about trying decarbonization. Overall very unhappy with the way I was treated by the company and the dealer. This is the 6th Nissan product I have bought in the last 20 years, and will more likely be the last one.

- Jonesboro, GA, USA