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Discussion Starter · #1 · (Edited)
Hello guys,

So I have a lot of research on this and I can't figure out what is wrong with my car. I took it to my usual workshop and the mechanic said that the issue might be because of the eletronic maps being not so efficient during colder temperatures.

Long story short, every time I start my car, it work fine , but then if I drive it, in 2nd, 3rd or 4th gear between around 1700 and 2000 rpm at gentle acceleration the car just starts jerking. You can drive it but you feel random short spikes of loss of power. No check engine light, no errors on ISTA.
If the car gets warmer then it is fine and never does it. However if I start the car in cold days and still let it warm for about 2 minutes and drive off, this still happens.
I've tried to plug my laptop to the car and drive it while recording the screen to try and check the if the live data has differences and I notice something.
The mass air flow (read) and the mass air flow (nominal value) sometimes don't match. This also is visible at idling speed of the engine. Just not driving the car and having the engine at idling speed the difference between the values is like half. However, driving it sometimes it gives very similar values.

I have also checked the EGR opening % and the difference is quite slim. And usually it just has some difference in the order of 1 seconds, I guess it is due to the refresh rate of the data.

I checked the soot mass and is at 10 or 11 grams so I guess that is fine.

Another important thing I noticed is that when I have the jerky hesitations when accelerating I hear (sometimes) like a whistle noise (like something is squirting or a "wet whistle", idk) coming from the engine bay. I still am trying to figure out a way to record this because I think that someone will be able to know what is happening by listening to that sound.

Edit: I replaced oil,all the filters that are present in the car, brake discs, pads 2 months ago, but the issues already were present before.
Also, my car is DIESEL

Do you experienced this in the past? Any suggestions for troubleshooting with ISTA?

Thanks ;)
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