Running issues.

[Stig_gti]

Morning
Had my stage 2 done at r tech before Xmas mk6 golf gti.
Everything was fine and for the last few weeks the only way I can explain it is, when on part throttle around 2 to 3k rpm I’m getting terrible surging and the power bogs down. Then all of a sudden it just fine and tears up the road.
Checked for fault codes non found. Any suggestions, full tbe exhaust power valve vwr intake, and gfb dump valve fitted last year. Never had the problem on stage 1.

[pudding]

What engine does your MK6 have?  EA113 or EA888?

When you say on part throttle it surges, do you mean it's hunting and can't hold a steady rpm to match a steady pedal position, or do you mean it bogs down when you tip into the boost?

[Stig_gti]

It’s the ea888.
So on part throttle it  bogs down and has no power and then of a sudden the powers back. It seems to happen just happen between 2 and 3k rpm just as boost come on.

[mo]

Sound like your Maf is dying try running some logs if you have vagcom.

[pudding]

Do all the usual checks.

Fault code scan
Plugs
Coils
Long term fuel trims
Chain wear correlation (cam sensor position, usually block 93)
PCV
Boost leaks
High and low fuel pressure checks
VVT function
etc

I had exactly the same problem with my ED30.  In my case it was too much boost, too soon.  My fault, I did ask for a very aggressive map     It was great on the day of the mapping, but over the following days that surging you describe started to kick in and got progressively worse.  The ECU adapted to the changes - in a bad way.  It didn't understand the massive load request and pulled it back somewhat aggressively.

It's all fine with a new map now.

Don't know if you have the same issue or not, but perform the hardware checks first.   If they all check out fine, it can only be the recent software change.

[Stig_gti]

Thanks for the help I will get it booked in to a garage hopefully aks.
But depends on waiting times. Will put up the results once sorted.

[Stig_gti]

Cars going into aks tuning on Friday the 9th of March will come back with what the issue was if found.