Hello all,
For the past 5 years my Jazz has been absolutely outstanding, the gold standard of reliability, however now it seems to be having some issues and I am having a bit of difficulty determining the actual cause.
- Jolting back and forth when accelerating, mostly only in 1st and 2nd. This issue became much less pronounced when I changed out my spark plugs but it does still exist to some extent.
- RPMs can fluctuate very minorly while driving,
- RPMs fluctuate a lot more while at a standstill, at traffic lights and such. Happens with A/C on (as expected i think?) but also without at times. Also attached is a video of the fluctuations while I'm also revving up the engine a bit, details at the bottom of this post. I do not have a video at this time of the fluctuations at idle, but typically it bounces between ~500-1K RPM every 10 seconds or so.
I have changed out the air intake filter, spark plugs, engine oil/filter and I have run through a bottle of fuel injector cleaner since issues started arising, I have also done a quick test on the coils by unplugging them one by one while the engine is running to see if any had no effect and all of them caused the engine to stumble which I believe means they are not likely to be a cause?
Another idea I have seen floating around is that a clogged/dead EGR valve could be the culprit and I do have a new gasket for it on order so I will be taking that off shortly to inspect it once that arrives. Unplugging the EGR valve entirely though did not seem to make much difference but it also did not throw any codes while unplugged which seems suspicious to me. I also plan to have a look at doing a valve adjustment at some stage, I have also seen this recommended but it has not been done in the time I have owned the car.
Another issue which I believe is unrelated but I think worth a mention is that when filling up the car, the fuel pump usually stops as if the car is full unless I pull the pump out a little bit, this just indicates a blocked vapor return hose right? Could that cause issues with fuel delivery and thus the engine behaving the way it is due to the lack of a proper amount of fuel? This issue started appearing about a year or so before any of the others.
I will attach a video of the inconsistent RPMs at a standstill, in this example I am attempting to hold the car at 2.5k, the A/C is off and my foot did not move a millimeter on the pedal, this is the car doing this on its own. (Turns out I am unable to attach video files, if allowed I will provide a link to the video)
Any help would be much appreciated
Cheers
