Unpredictable boost issue bh5 tiptronic

[Prodrivebugeye]

Hey guys, first time back in a while.

The wife has a 2000 bh5 gtb tiptronic and its been doing funny things for a while now.

It will frequently hit about 5psi primary and then tries to hit secondary with a huge vod.

Then as if nothing has happened it will boost fine again out of nowhere. Its done 120k and been well maintained for the last 40k by myself.

The only error codes i get are code 66 and afm. Have cleared the codes and cleaned afm. Seems to make a difference for a little while after ecu reset but then falls back into the same routine. Wife says it happens a lot in the mornings on her way to work.

Issue cropped up after car was left at mechanics for a wof so im not sure what happened there but it was fine that morning and not the same since.

Any ideas? Rarely gives a code 66 when issue is present so Im stumped

[Rosssub]

Make sure no hoses have popped off anywhere, then try giving the BBOD a clean out, probably just a clogged vac line or solenoid:

http://www.uklegacy.com/forums/index.php/topic/11043-code-66-and-boost-issueshow-to-clean-them-out/

[Marky]

I'd be wonder if the afm is still being a fckwit

Otherwise seems like maybe a sticking open secondary relief valve maybe?