What’s up guys, my 2006 G35x has had some trouble with cold starts recently. I only have about 93k on it as well. In the morning it cranks normally but the engine almost struggles or sputters for half a second and then it starts. It has started up on the first try every time but it’s a little rough. Once it has been driven, it starts up perfectly. If I immediately turn it off after the struggling first start and do it again, it’s completely normal.

I don’t have any lights on my dash and my G has been driving normally. The only issue is the first cold start of the day. If I leave it for like 6 hours after driving and try at night, no issues. I had my battery tested last week and was told it was bad so I replaced it. That didn’t solve the issue, so I tried tightening my belts that were slightly loose. I replaced them both over the summer so they are new. That didn’t help either, I still get the rough cold start. No odd sounds on the start, the RPMs are normal, no fluid leaks. My spark plugs only have about 15k on them so I doubt it’s that. With the new battery it’s a fast crank but the engine sputters/struggles when it’s about to turn over.

I’ve read that Nissans sometimes have issues with cold starts due to fuel taking an extra second to circulate in the morning? I was planning on trying some fuel injector/system cleaner tomorrow to see if that solves the issue. Any ideas? Thanks for the help guys!

 

When you are starting the car, do you let the key sit in the 'ACC' position? Typically this is when the fuel pump will prime (build fuel pressure).
You can try doing an idle relearn and throttle closed procedure, maybe an ECU reset as well.
For what its worth, older Honda's can be hard starting when the coolant temp sensor goes bad. Buddy of mine with a Del Sol had starting issues when cold (car would idle rough for a second or two, if not, rough idle and immediately stall out). New coolant temp sensor solved it.

 

I don't let the key sit in the ACC position, when I start the car I just turn the ignition and start it right up. It isn't idling rough or stalling, the engine just sputters for a second when turning over at first. Everything else is completely fine, no issues. Not quite sure what it could be.

 

Scan for codes, could be single trip code (hidden code) that it stored to point you in the right direction.

Regardless of mileage, pull the plugs and inspect them. Most everything you need to know about a motor you can tell by reading the plugs.

 

thanks for the reply. I ran some Techron fuel system cleaner through two days ago when I filled up. It has started up normally the last two days on cold starts which it hasn’t done in a few weeks. I’m hoping that solved the issue, if not I’ll proceed with your suggestions. It’s been warm the past 2 days but it went away for now. Pretty weird

 

In my experience when you are experiencing cold start issues (more persistent/prevalent the colder it gets, especially at freezing temps) the issue is usually a failing intake gasket, when cold gaskets tend to leak more, once they heat up/expand they seal up the slight gap better.

It doesn't hurt to check the tension on things like intake clamps, retorque intake bolts to factory specs, etc.

However I still think you'll find the issue while pulling the plugs, maybe one is fouled, or oil in the spark plug well, damaged coil pack, etc.

 

Hey Alex, I have the same exact issue as you. I also bought the Techron Fuel System Cleaner and noticed it helped for a few days but back to a rough cold start for me. When you used the Techron, did the problem keep persisting? If it did, were you able to find any solutions? I'm debating on replacing the fuel pump but wanted your input before I actually buy it.