Hey guys, I need help figuring out this problem that has been occurring for the past couple of weeks. So I just got my Catalytic converter replaced, USED, and the car had been running perfectly fine until couple of weeks.

Around 1000 -2000 RPM once you accelerate very slowly the car seems to hold back and then move forward, like a little jerk occurs.

When you drive at a constant speed its fine. When you accelerate fast, you dont feel anything. I got my intake replaced with K&N, cause the previous one was quite dirty. But no difference.

I don't want to say its is the Catalytic Conv, for there is NO LIGHT, NO ENGINE LIGHT ON, NOTHING.

NEED your help, need to find out what this jerk is and what may have caused it to happen.

The car has always been serviced at infiniti, and has 120K currently.

2007 G35 Sedan, Journey.

Love this car!

 

[QUOTE=ssh1786;5918940]Hey guys, I need help figuring out this problem that has been occurring for the past couple of weeks. So I just got my Catalytic converter replaced, USED, and the car had been running perfectly fine until couple of weeks.

(Used)<---- That Might Be The Problem..

 

I think this is a common issue for a lot of our cars. It's because our cars are trying to pick which gear to go into therefore it goes into this "stall" mode.

[QUOTE=sdonabo;5919016]
Well saying that it's used is an ignorant reason. It's not uncommon for our cars to do this from what it seems, did you get the transmission flash yet?

 

Yeah, what with the DBW setup in these cars, it sounds much more like an issue there. I wouldn't be thinking cats, I'd be thinking "why is the ecu delaying throttle response?", and it could be very well be because it's fumbling with a tranny shift issue.

 

Well saying that it's used is an ignorant reason. It's not uncommon for our cars to do this from what it seems, did you get the transmission flash yet?[/QUOTE]

Yes, the car has had it's transmission flushed back at 80-90k. I'm just curious to know why would you say it is an ignorant reason...

 

See I know how it feels when there is a tranny shift issue, can't really say that is the issue. Feels like some sort of air flow block... Cause it is not happening when it shifts but rather at a certain rpm.

 

If you haven't done so, try and do the ECU reset doing the foot pedal method. It's too easy to do to NOT try it.

 

Look for TSB # ITB11-018

If somebody has the option to post a scanned document, send me an e-mail and I will fwd the TSB to you.

Ocuriel79@yahoo.com

It boils down to a PCM reprogram.

 

What tools were used to replace the cat converters? This issue is common when people use a hammer or impact wrench to remove the cats. The primary O2 sensors on the manifolds can get damaged with the weakest of impacts and once they're damaged the car will have this 1000~3000rpm hesitation. Usually however, this hesitation is accompanied by a CEL.

 

My car started doing the same thing this week. Disconnected power to the car so i can take the steering wheel off. Now i get a slight hesitation when i accelerate. It always happens under 1000 rpm in 1st gear. You feel like the car is going to turn off but then it accelerates fine. Could it be a cam sensor issue?

 

Nevermind. Fixed it just now by disconnecting the battery again. All is good with the G now.

 

Its a Temp fix, this sounds more like a Maf problem, clean it or replace it with a new one.

 

So my 06 G35 AT sedan since I bought it last month has had sluggish acceleration under 2k rpm, when under 2k rpm I have to be very gentle with the pedal. And when accelerating under 2k rpm the engine sounds like it’s whirring and most of the time I hear a tapping/creaking sound coming from the front of the car. once it hits 2k rpm it feels like it shifts a little rough and the rpm’s go back down to around 1200 after that it accelerates a little better unless I come to a stop and accelerate again it goes back to being really sluggish. And if I accelerate to 2k rpm without going past it and let go of the pedal the car jerks forward a bit. It also jerks forward when coming to a stop unless I apply the brakes really hard. And I get very terrible gas mileage I get maximum 200 miles per tank. If I accelerate fast past 2k rpm the car feels fine and on highway I get no issues runs very smooth I’ve even gotten it to 120mph on a empty highway late at night. It’s just the sluggish acceleration.

 

Check this thread as well.. I'm having the same issue and I've replaced all kinds of stuff trying to fix it. EVAP purge valve, canister valve, new spark plugs and coil packs. I've done all the pedal dances to reset throttle position, pedal position, ECU reset..... nothing. It only likes to do it when it's in first gear trying to take off... for example, in neutral or park, is doesnt stutter at all.. but in DRIVE, it stutters just under 1000 as i try to start moving. Once it starts moving it isnt as bad like if i let it roll some before i try to accelerate. but if I hold the brake and accelerate to just under 1000, it stutter worse and almost shuts off like its completely off its ratio... anyway// Mine runs good when it's cold but starts the stutter when its warm. I just called my local Nissan dealer today to ask about the transmission reflash according to Ocuriel(2011 sheeesh) from the TSB # ITB11-018 (service bulletin)
https://g35driver.com/forums/g35-sed...tter-code.html
I'll update both posts with the results

 

Update: Unfortunately, my ECM was not on the list therefore not eligible for the ITB11-018 bulletin. no work was done to the vehicle. Not sure where to go from here.