Hey guys, so I posted about having gas mileage problems earlier. I changed my filters and ran a bottle of Redline SI-1 through the fuel tank. It seems to have improved, but the real test is coming up over the next few weeks as I run my tank down here in Scranton (where my mileage is particularly bad).

Anyway, I noticed after the Redline SI-1 (this may be coincidence that I only noticed it after I ran that through), that at certain speeds I get a sputtery/jolty drive. I noticed that this happens more often when I just start driving in the first 10 minutes. What happens is when I am actually accelerating very casually/pretty slowly at some point my car starts sort of ..."bumping" and if I keep my foot on the gas steady without increasing the pressure, the bumping continues steadily. If I gas it hard at that point, it goes away. The bumping sort of feels like you're driving and pumping the acceleration on and off, on and off every half second or so. So every half second the car sort of jolts. Feels like it accelerates for a split secondm then stops accelerating and then accelerates again but this cycle happens very quickly and continuously so it's just a sort of bumpy ride.

This worries me a lot. I am not sure if it has something to do with the fuel being fed to the motor inconsistently, or if it's a transmission problem of some sort.

Anyone have a similar experience? I don't know if I can "reproduce" this at will...so if I went to Infiniti, I have a feeling they'll just send me off with a "cannot reproduce problem"...please help! I guess this is what I get buying used

 

Not sure what the history is on your car but for auto's there are multiple ECU reflash TSBs...one of which deals with cold start issuees. Did you have any of these done? Also, if you are still under warranty, there is no reason not to hit the dealer. Even if they cannot replicate it, the report will be on record. You can always go back if you figure out how to replicate it for them or they may even figure out what's wrong through diagnostics. Don't necessarily feel you have to figure out the problem yourself.

 

1)Not sure what the history is on your car but for auto's there are multiple ECU reflash TSBs...one of which deals with cold start issuees

Sorry--I am not really sure waht that means except that it is something electronic lol. I am tech savvy but not car savvy (yet)...just got this G.

2)The dealer is like 2 hrs away from me and I'm in med school so I have to wait until Summer at this point to go (June) unless it's a real emergency :-/

 

This is a simple fix. Change out the spark plugs and or coilpack.

 

Hey, would you mind explaining to me what the issue is?

I am not very tech savvy, but I thought the spark plugs are necessary for ignition--I didn't know they were used while driving. What do they do? And what is the coilpack? Thanks for answering my noob Qs

 

PS--can this have been affecting my gas mileage too?

 

Its an 07 so take it your dealer and its should be covered under warranty since the plugs on the G are supposed to last a 100k, if that is in fact the problem.

 

Do you think I can get this serviced at Nissan? Or does it have to be Infiniti?

 

So I just read service bulletin ITB07-045a and it sounds somewhat similar to what's going on for me. Do you guys think this is the problem or is it the spark plugs, etc?

 

This exact same thing happens to me when I would drive up a certain hill every morning while my engine was still cold, feels like the car is accelerating/decelerating back and forth back and forth, check out the link I posted it seems to be a common problem.

Sounds like this,
https://g35driver.com/forums/g35-sed...ph-60km-h.html

 

If your car is misfiring, I would think a code would come up. I would not finger spark plugs as a likely suspect. Man, 2 hours is a long drive from the dealer. I would plan to visit the dealer some time well before your warranty ends.

 

Could be your plugs got fouled with gunk after running the FI Cleaner.

 

Nah it is the one what leffizet suggested. Just check out the link and see if you have it at that speed. If you have it around 40mph than look no further.

 

^ what he said!

 

I'm not usually on a road that I can easily hit 40mph with gradual acceleration so this may have to wait a bit to get checked. I hit 40 today, but it was semi-gunning it and I couldn't feel it so well. Also, every time i hit 40, I'm going downhill so I stop accelerating. Lol...I think that it is 40mph when it hits...I will double check as soon as I get a chance. Thanks for the info guys! Will update if this is not actually it.