GU RD28 boost spike, engine power plateau

[UVB76]

Hey trollers,

Over the last few weeks I've noticed the boost on my GU RD 28 spike every now and then. Usually the boost gauge reads 10-11psi flat-foot, but now when it spikes it goes to ~13psi then drops to 9-10psi and won't budge until I shift down or get more revs. Also, when the boost drops, the engine power seems to plateau or sometimes the power feels like it's bunny hopping. The problem is, it doesn't happen not all the time :\ I've been able to notice it usually after ~45mins driving, when sitting at ~70kmph in 4th gear through to 90kmph in 5th.

I didn't find cracks/splits in the intercooler pipes, not really sure where else to look? Any ideas?

Cheers!

[drz400y]

Check the waste gate operation to make sure it's extending soothing back and forth. But a regulator and air hose from an air compressor onto it, slowly apply pressure and watch the rod for smooth movement. Won't need any more than 15psi to check it out

[UVB76]

Cheers mate, appreciate the suggestion. I'll suss it out tomorrow.

[UVB76]

So an update on this one.

I didn't get around to checking the wastegate yet, just haven't had time. But then I had a great idea to check the ECUTalk and it was reporting the error "12 AirFlow Sen". I gave the MAF a clean with some MAF cleaner and everything seemed good for a few days, but the strange boost behaviour is back again.

What do you reckon, do I need to check the wastegate again? Should I replace the MAF? Is there another sensor I should be looking at?

Cheers!

[Funwin]

Bought a ECUTalk after reading this thread. Think I have the same problem - https://youtu.be/C4Q-OMPUxm4