Been going on on and off for over a year now. Under acceleration the car stutters badly. Worse at lower rpms or when the car is in a higher gear “lugging” around. Idles fine. Revs fine in neutral/ park. Only does it under load and after the car is warmed up. If the car doesnt do it at first, it will do it after I turn it off (say i go into the store or to the gym) and it starts doing it as long as the engine hasnt gone cold. Starts up fine every time. Doesn’t throw a CEL. No error codes. Even had the dealership look at it and they also couldn’t find any hidden error codes. No vacuum leaks that I could find. Smoke tested it but I don’t know that that’s the most effective method in looking for them. Dealer told me they think it’s my MAF sensors. Replaced both myself and the problem was fixed for a few days but has come back even worse. Used to be able to give it enough gas that it’ll kind of “break through it” and stop stuttering but recently that doesn’t even work. Does it worse in cold weather if that matters.Dont know what it could be without any codes and don’t wanna just throw parts at it. Anyone ever dealt with this issue? I’ll link some videos

https://youtube.com/shorts/zS6bokFThWk?si=ZZsswuZVj3n5fQyU

https://youtube.com/shorts/TdwnrWPGNjc?si=lfIyoyzDRqT08XpS

 

Could be a number of things. Spark plugs, Ignition coils. air filter, low fuel pressure due to dirty fuel filter, fuel pump and ECM or any number of sensors. It may even be a transmission issue. Do the engine RPM's drop, increase or stay the same when it is bucking? It is difficult to diagnose if you are not getting any codes.

 

Yeah so as of today I was able to pull a P0174 code, which is System too lean bank 2, which would seem to be a relief except now the problem has become even worse, on my way to work today it began bucking harder than it ever has and my radio screen began shutting off for 10 seconds at a time and them coming back on after it calmed down a little. So now i’m stumped because this problem seems to be electrical but I have a lean code. Not sure what I should be tackling atp

 

You can start by checking your battery, alternator connections and most important, ground connections. As these cars get older oxidation builds up at ground points creating issues with sensors and voltage drop due to elevated resistance.

 

check your AFR under load *use torque or compatible app). if it leans out, you fuel pump can be on its way out.

 

Most likely CAM and Crank sensors will be going out. They do not throw codes but do tell you Bank 1 or 2 is lean. Read my thread and you'll find your answer there.
My thread should be stickied! Long and rough warm or hot restarts

 

Pull/inspect the plugs. Check the primary engine/chassis ground wire located on the right/passenger side of the engine. It's the bigger wire, can't miss it.

 

After all this time it turned out to be my alternator. I noticed that whenever I'm giving it gas/ the car is moving, my interior lights flicker. The moment the car comes to a stop they don't. I knew this had to be connected because the car only would stutter under load but idle perfectly fine, just like the lights only flicker under load but are fine at idle. This on top of my infotainment screen shutting off while it was happening one time told me that this issue is connected and definitely electrical. I started by checking all the grounds, and everything looked fine. My negative terminal ground had a bit of corrosion and there was dried up acid all around it due to a past battery leak. So I just swapped in a new negative terminal from z1. Problem persisted. I then noticed from my car charger with a voltage reader that under load my voltage fluctuates like crazy, between 13.1 all the way up to 16.8. I knew slight fluctuation can be normal but not that much. So I was thinking alternator but I had never heard of an alternator giving these kinds of problems while never having charging issues. I planned to get it tested it but my boy whos a mechanic wanted to look at it. Right away seeing how the lights flicker along with the misfire like symptoms he's like yeah this is definitely alternator. We drive up to advanced to get it tested and sure enough that was the issue. This doesn't seem like a common problem as I was unable to find anything on forums when I was going through it. Typically when alternators go people deal with charging issues and such. So if you're dealing with this issue definitely get your alternator checked cus it can definitely caused intermittent misfire like symptoms that you would think is engine related all while throwing no codes.

 

I'll keep that in mind as i bought my G with the alternator already replaced.
Corroded battery terminals cause resistance between battery and the alternator, so the alternator runs more electronics when the battery should and that would explain the alternators 'premature wear'.
I found that NOTHING helps in preventing acid vent through the posts of a 'wet' battery, tried many brands and in hot places like Florida, the heat just boils the acid in them. So then i've switched to AGM and no more rabies on my battery posts!

 

Yeah def keep it in mind bro. I've never had these kind of symptoms from an alternator as usually when my alternators have gone in cars i've owned I would just have battery charging problems, so all this time I thought it was engine related. When I pulled the alternator I found that the previous owner threw a damn duralast in it lmao. As im sure you know OEM is the way to go. My battery posts have been fine but it was the negative terminal ground that looked kinda sketchy. Looking back it wasn't the issue but I was desperate after all this time of my car running like sh*t, so i was willing to try anything. I saw your reply and was ready to start ordering cam/crank sensors until I figured out the real issue. If the alternator in yours isnt oem I definitely recommend having on on standby, but I'm sure your previous owner isnt as dumb as mine to throw a mf duralast in there lol. Car is running flawlessly now

 

Like too many on here have spoken about the GROUNDING cables and their connections on these cars and that seems to be the most important starting point of any troubleshooting on these cars. I've tested the 'extra' grounding setups like the one at Z1 but it makes zero difference unless you can see your grounds are heavily rusted out and look green.
Whenever i've had a alternator failing, the lights would either flicker or pulse on idle and stay steady on higher RPMs. So this is a first for me..

One thing to keep in mind is when the power steering pump banjo bolt area starts to leak, the oil will go directly over the alternator and that will also damage it. It had to happen in mine because the new alternator that was in it when i bought it, it was already 'juicy' from the PS pump leak. I've soaked it in straight purple degreaser for few minutes, then rinsed it good, blew it out with compressed air and sprayed WD-40 all over it. 13 months later, still works fine.