Pulsating RPM while accelerating and fixed speed

[nammaris]

Greetings and salutations everyone.

 

I hope someone can help me with my issue:

When driving at at fixed speeds (fixed pressure on gasoline pedal) the will be some lost in power for a second or second two and then back to same speed, and it is pulsating (like its has a fixed time to keep occurring).

Same thing when i accelerate, for a second or two it decelerate and then back to acceleration.

 

Its been there for a while although I have changed my spark plugs and clogged injectors (they needed changing and hoped it will be solved), but still no change at all.

 

Thank you in advance for everyone.

 

Merry Christmas!  :party:

[KenONeill]

This sounds a bit like fuel starvation. Have you changed the fuel filter in the last 64_000km?

[nammaris]

Thank you KenONeill for your reply.

I don't think it was ever changed. It's around 79,000KM now, and i doubt that any major changes were done as well.

Could it be anything else? Because it feels like it's synchronized with something.

[KenONeill]

I'm not certain it's the sole cause, but the fuel filter is cheap and needs doing anyway. Beyond that it means reading fault codes from the engine management system (EMS).

[Moztune]

Is it a deceleration or a hesitation? Like the engine stops breathing for a second? I've noticed you've got the auto, what's the gear changes like? Vw declared the auto "sealed for life" but that's not the case and a lot fail at the 100k miles mark due to lack of maintenance.

[nammaris]

Today i took the car to the mechanics and changed the fuel filter and the timer belt. Made them check the gear oil, they added one liter as they claim.

The gear had some jerky shifting at times, and still the same after topping the oil. And the gear had some jerky shifting some times and disengagig at low temperatures in the morning (sometimes, not always at 0.8 rpm and at full stops) and reconnects the second u press the gas pedal a little, and after driving for a minute or two, it will not occure again after that.

[nammaris]

@Moztune, i really dont know if its hesitation or stops breathing for a second, but it loses power at that instance that make the rpm go down (not sure, but i think even if I press the gas pedal more at that instance, it doesnt reapond).

I will try to make a small video and upload it soon.

Thank you everyone for your inputs and support.

[Adz_VRS]

I had this issue for quite some time. Tye car was worse to start on cold mornings and actually got to the point where it wouls misfire until warm. I always carried out general maintenance i.e oil, filters, plugs and even coil packs. What actually sorted my hesitation in the end was the replacement of my fuel pressure regulator. This cured all my rough idling, pedal hesitation and cold start misfiring. I hope this helps.

[nammaris]

Happy 2017 everyone.

 

@Adz_VRS thank you, i will look into that. As for the start, i have the opposite, i sometimes have problems with warm start (sometimes it doesn't start at all until its cold enough). One friend told me it might be the fuel pump. So is it possible that this pulsating issue is from the fuel pump as well?

[nammaris]

Today I took my car to the mechanics because the there was an oil leakage (ATF), and took the chance to tell him about the pulsating RPM, they checked the fuel pump and the fuel pressure regulator, they came back with no codes and didn't see anything wrong with it.... =S