It started yesterday, i noticed if i go over bumpy roads on an incline, around 2500-3000rpm and light acceleration, the engine would jerk violently and there would be no power. Its very intermittent. I can't seem to replicate it when i want to but chances of it happening increases over a bumpy road.

I also happened to fill up the tank yesterday so im thinking possible bad batch of fuel? What about a loose connection somewhere? Where should i start checking? Im going to buy a bottle of octane booster

List of mods currently installed:

HKS single turbo kit
Walbro fuel pump
DW 600CC injectors
HKS spark plugs

Cheers

 

What are you using for the tune? Sounds like bad tune or lack of fuel. Any check engine codes?

 

Could be many things.
Do they sell Sea Foam in Australia?
I'd try some in your fuel.Go from there.
Works great for me in all my vehicles.

 

No CEL?

 

Yeh unfortunately no CEL. No seafoam but i know an alternative. Im really hoping its a bad batch of fuel.

I have the HKS f-conn and its not a bad tune as this happened suddenly.

 

Hmm, sounds possible, it's also making me wonder about fuel filters... i've not looked for it on the 350?

 

Don't think 350's have a fuel filter.

So on my way home from work, it was getting more frequent so decided to do a few tests:

- It definitely "activates" on incline or going over a sharp bump. There was a steep slope i was going down, the stuttering lasts for 6-7 seconds. It sounded like a rotor, "bap bap bap".

- The harder the throttle was pressed before it starts stuttering, the more violent the jerks was.

- Could smell fuel when it starts hesitating

- Could not rev even if i pop it into neutral, so the problem exists even under no load.

- Idle is fine

- No certain rev range, so far its only happened within 2-4k rpm but thats because i spend most of my time in that range

Will this damage my spark plugs?

Normally, the symptoms suggests its a batch of fuel but it only happens on certain conditions and not constant...

Just want more advice before i go and syphon $90 worth of fuel

 

Hmm, so, seems they do have one, it's a mesh screen on the fuel pump.

As for the problem, was it really *only* when you filled up? no other factors you can think of?

If you're smelling fuel, it's not burning, either because it's not 'pure' enough, or because there is a spark issue. Spark plugs fouled? Bad earth? How about when the engine is cold?

 

Yeh, definitely started on the same day i filled up. I had 1/8th of fuel left and decided to use a service station that i didn't normally use, but obviously still using premium fuel. Then on my way to work which is 40km (25miles) i noticed my first stutter close to my work place when i went over a bump but thought nothing of it.

Then on teh way home (another 25miles trip) it started getting frequent. So im assuming the 1/8th of good fuel that was left was being used on the way to work and the bad batch started kicking in soon after.

I searched and found that you can't syphon the fuel in the 350z, so im just gonna run the tank dry and replace the sparkies. Lots of smoke when in boost while the car is hesitating and im WOT.

Fuel gauge now showing only 45% left to go. Im really hoping its just a bad batch of fuel.

 

Hmm, i'd be tempted to throw in a couple of bottles (if the bottle is a dose) or one whole bottle (if it contains several doses) of your leading fuel treatment until the tank empties, just in case, sounds like you're boosted so i'd be even more careful.

 

I guess it was fuel, im down to 1/8th of the tank and the last the 50-60miles, no stuttering and hesitation. Will still do an oil change and spark plug inspection for peace of mind.

 

Interesting, keep us updated.