afr0puff

iTrader: (1)

Has anyone had this problem? My car chokes/stutters at wide open throttle. I will be in gear for a while, then decide to floor it. It goes like it should, but then it chokes and lunges for about a second and then it accelerates again. This only happens at WOT. If I accelerate aggressively but do not floor it, the car is fine. Happens in all gears except 1st. Some gears are worse than others. Doesn't happen all the time, but frequently.

SSZVirginia

iTrader: (1)

Is the air conditioner on when it happens?

tbcz

Perhaps the tires are losing some traction when you get on it that hard and invoking the traction control.

afr0puff

iTrader: (1)

A/C on or off, it doesn't matter. VDC is off. No chance of breaking traction in 6th gear. It happens around 4,000 RPM. So I'll be cruising at 20mph in 3rd at 1,800 RPM. Take an entry ramp onto a highway. Stay in third and floor it. Car takes off like a rocket. Once it hits 4,000 RPM, it noticeable sputters then takes off again to redline. This happens 50% of the time.

If I'm in 6th and just want to pass someone quickly without downshifting, it will start moving, then stutter, then continue moving. It's the kind of stutter you get when you see someone learning manual transmission for the first time. That herky jerky motion, but this isn't when shifting gears. It's after I've been in gear for a while.

ares

iTrader: (2)

sounds like something youd see on a weedwacker or something, when its warming up and you gas it, it floods itself with fuel and takes a sec to burn it all off and start accelerating the RPMs.

but with modern fuel injection that seems odd that it would flood the engine, specially since Im assuming your well at operating temp ect.

OneFast944Turbo

Make sure your using good gas.. Change or check(take off and blow into) fuel filter, fuel pres reg., i seriously doubt the plugs are carbon'd but you can check.

Jetpilot718

Hows the condition of your intake? Is it an aftermarket intake? Maybe theres something causing the MAF to read funny. I dunno, too much computerization in cars these days to tell. Go to Nissan, see if they can pull down some code from the diag. port.

afr0puff

iTrader: (1)

The car is stock. I only use 93, but I switched to Ultra to see if the problem would go away... no luck. Maybe even worse. I've taken it into service once before and they weren't able to duplicate the problem. That was two weeks ago. Now the problem is more severe and affects all gears instead of just 3 and 4 like it did before. I have a service appointment for july 9th, but that's a long ways off.

Can I check the fuel filter myself? or is that a big production?

sausage5000

is it a 2003 Z?

people, correct me if i'm wrong, but isn't the hesitation issue that the 2002-2003 altimas experience sometimes seen in 2003 Zs?

isn't there a TSB for hesitating Zs? my story goes like this:

i chatted with a guy a few months ago that had his 2003 Z ecu tested, and it kicked one of the same bad codes listed on the altima TSB. The tech flashed his ECU with an update he downloaded, and the "N/A imitation turbo lag" was fixed.

ZxRage

I have the same problems that you are listing and I figured out what was causing it. I changed my oil to full synthetic 5w-50, then I started to get a whistling noise when accelerating. It turns out that the oil backed up into the intake manifold and broke the seal between the top and bottom intake plenum, when I removed the top plenum, I could see oil around that gasket. I cleaned off the oil and used silicon on the old gasket to create a better seal and the problem went away.

Here are a few questions for you. What kind of oil are you using? Can you try to take off your upper intake plenum and check to see if oil has broken your seal?

Let us know what you find out.

afr0puff

iTrader: (1)

Mobil 1 5w-30 since 3750 miles. Experienced problem at 20k. As for checking the plenium... is this all I have to do, under the "removing" section and I will be able to see what you are talking about?

http://g-owners.com/article_read.asp?id=22

nitrousoxidex

iTrader: (4)

Maybe you should try using that fuel injection cleaner stuff that you put into your gas tank. I think it might help...maybe...

afr0puff

iTrader: (1)

Manual says not to use any fuel detergents. It can cause the engine to run to rich or lean... i forget which one.

ZxRage

Hey Afro,

Okay, in the picture from step 11, you can see the gasket that I am talking about, it is the one that outlines the top portion of the lower intake plenum. Take that off and check to see if there is any oil that might have slipped past the seal. If there is, clean it out, and then use a silicon gasket maker with the old gasket and put it back together. Let it sit for around 24 hours and then take your car back out and see if you are having the problem again. With my intake plenum, the seal was broken near the back portion of the intake plenum near the throttle body.

Good luck.

zzzya

iTrader: (2)

Have you been hard on the clutch? Is the engine actually bogging or does the car simply not accelerate for a short period while the rpms are still holding steady or climbing? Is it possible when you are punching it, that the clutch is slipping for a bit, then grabbing? Any funny smells when this occurs?

zzz350

I have 10K on my Z and was just about to switch to Mobil 1, now you guys have me nervous about the switch, based on this discusssion. Should I switch or stay with dino?

afr0puff

iTrader: (1)

It's like I hit the rev limiter at 4,000 rpm three or four times before I punch through. No smell. Would it be the clutch slipping considering I've been in gear for two miles and I'm not shifting, I'm just flooring it.

DragonGcoupe

HEY. I finally got someone with the same problem. What gear does this happen to you in? For me it has happened in first.

Such as the other day, I was fully engaged in first, normal acceleration. But then I decided to floor it, and then it feels like the car starts to climp in RPM but then it jerks and doesn't go smooth for a while. When this happened, I just pushed in the clutch and went to second. When I WOT again it goes smooth.. I want to know the real cause of this.

afr0puff

iTrader: (1)

all my gears except 1st.

sausage5000

doh! i reread my post, and it makes no sense. i meant something closer to... the z kicked showed a bad ECU code, just like the altima problem. of course its a diff ECU though. apparently there is a TSB for hesitating Zs, but i don't know what specifically fixes the problem. my altima w/ VQ35 had the computer replaced, and the ECU reset to fix the described heitating issue.