# 2006 Altima 3.5 with a misfire



## BrokenAltima (Oct 10, 2015)

Hi,

I'm new here and have never posted on a forum like this before, so please bear with me...

I have owned my 2006 Altima 3.5 SE since 2007 - at the time of purchase, it had 15,000 miles on the clock. It had a rough/loping idle for several years, until I found a Nissan dealership that took the time to raise the idle to 750 RPMs, which made it run as smoothly as a Lexus. I've continued to go to this dealership and have never had ongoing problems with my car until recently, when it decided to stall at a stop light. I immediately took the car in and the techs found no fault codes - I requested that they replace the cam and crank position sensors, as I had read that this is one of the Altima's issues. I also had them replace the MAF sensor, and throttle body. 

I've been a little nervous about my car since this happened about a month ago, and my fears were confirmed again yesterday while sitting at a light...the car was running perfectly smooth, and suddenly I felt a big jerk (almost like a car rear-ending me). It didn't stall, but that may have been because I quickly two-footed it to give it a rev. Both times that this has happened, the engine is fully warmed up.

Another thing that I have been struggling with is this heavy vibration that I get when the engine is cold and put in reverse (if you wait about 15 seconds with your foot on the brake). The vibration feels out of character for this car. I've had the motor mounts and transmission mounts replaced within the past 3-4 months, and this made no difference.

My car only has 65,000 miles and I have taken excellent care of it...I've replaced the following parts within the past 6,000 miles:

Spark plugs 
All 6 coils
Valve cover gasket (twice)
Timing chain 
Cam and crank sensors
All motor and tranny mount
Throttle body with sensor
MAF sensor
Radiator hoses
Cleaned fuel injectors
Had air-idle volume relearn done

I don't know what else could be causing what feels like a random, and pretty harsh misfire at times, as well as the roughness in reverse. There is no check engine light on, and the manager of the dealership told me that my car is in great condition...the only other symptom that I can detect is some variance in idle speed which is not registering on the tach - when warming up in park, you can hear the pitch of the engine change slightly every few seconds or so...it didn't used to do this. It holds pretty steady around 1,200 RPMs when cold, but sounds like it is having to work to keep idle smooth. 

I apologize for the long post, but I am really hoping that someone can give me ideas of what us causing that misfire. I am almost ready to sell my car over this!


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