After 257,000 kms, I'm finally having a problem with my motor. It still starts well and there is no problem when cruising along but while I'm accelerating and the revs drop due to the auto gear change, the engine seems to lag on power in the new gear. It's like a momentary dead spot for a few seconds. It is more pronounced when the motor is cold. Anyone had this problem?

I know this is an old thread, but there ware never any suggestions as to the cause of the issue.
Now my TD4 is mostly running at full power, after I replaced the damaged head with a low mileage replacement.
I've another issue, where the engine seems to drop off boost on the gear change (it's a manual). This results in an amount of engine braking taking place for a second or so, before the power comes in again.
I've also got a slight misfire when it's cold, but I think this is due to the continuing issue with air in the fuel supply line. I'm hoping a replacement genuine filter solves that issue, but this drop in power is there on every gear change, when I'm using some power.
Any suggestions?
Cheers. Hyundai Ioniq 5 Ultimate. The family car.
2009 Rimini Red SE TD4. Gone.
2006 Tonga Green i6 HSE. Gone.
Audi A5 convertible, my daily driver.
1972 Hillman Avenger GT, the project.

Last edited by Nodge68 on 30th Dec 2021 10:14 am. Edited 1 time in total

Wow, over 800 views, and no responses. Anyone got any ideas on this? Surely this can't be an isolated case.
 Hyundai Ioniq 5 Ultimate. The family car.
2009 Rimini Red SE TD4. Gone.
2006 Tonga Green i6 HSE. Gone.
Audi A5 convertible, my daily driver.
1972 Hillman Avenger GT, the project.

Generally, such symptoms were consistent with (improper) EGR functioning and a modified air flow (restrictions) due to the deposits of soot and oil gases on the intake tract.
Mine started to do that and as soon as I've blanked the EGR all returned to normal.

Wow
Thanks for answering Alex.
As it happens, the EGR does have a blanking plate in place. However there's no soot or deposits in the intake system, as I cleaned it thoroughly when I reassembled the engine last year, its still spotless inside the intake now.

However I've managed to solve the issue I believe.

I've had a couple of hours with SDD in it today, doing various calibrations on the engine.
I've reset the fueling adaptations (it's had replacement injectors anyway), and also done a calibration on the throttle body, and air path calibration too.
The result is the issue has gone, or at least reduced to a normal boost drop off levels, rather than feeling like compressor stall on the gear changes.
I'm thinking that the throttle body wasn't calibrated when it was change (before I got it), so believe this was causing the issue.

I'll report back should the issue return.

For now, thanks. Hyundai Ioniq 5 Ultimate. The family car.
2009 Rimini Red SE TD4. Gone.
2006 Tonga Green i6 HSE. Gone.
Audi A5 convertible, my daily driver.
1972 Hillman Avenger GT, the project.