Seems to be a common theme at the moment, and as the search is down...

I'm getting big hesitation on boost, like fuel cut but for only 1/2 sec at a time. The car doesn't hold more than about 0.7 bar boost though it's normally good for 1. This happens no matter how warm/hot the car is. Idle is fine, normal driving up to the higher boost pressures is fine, though I have once experienced hesitation going uphill at low RPM in higher gears.

Last service was fine, only about 4 months ago. Plugs were ok then. I'm guessing cleaning the boost solenoid and MAF sensor are a start (a guide with pictures would be great if anyones got one!), but I don't know if these symptoms are indicitive of either. I've had fuel cut once before ages ago so I know what it feels like and it's not that!

Can anyone identify a likely fault? The car is a 96 Sti 2 Type RA.

 

KRM,

I`m having the same sort of bother with my `99 ppp`d turbo as it seems to hesitaate for about half a second when i`m giving it a bit of stick at 4250rpm. It`s exactly the same place each time.

I`ve had suggested the MAF, boost solenoid, coil pack and even plugs but no definitive answer.

This seems to be a more and more common occurance that somebody should have an answer?

 

Worth getting the Turbo Duty Valve Solenoid checked out, mine was recently replaced £140ish and works perfectly now.

 

I gave the boost solenoid a clean as it seemed a good place to start - took the hoses off and sprayed carb cleaner into each one and got some black looking liquid coming out in return! I took it for a blast afterwards and it seemed to have made no difference to start with, but after a few goes it went cleanly to the redline in all gears

This seems to be consistent with what I've read. The car gets serviced and has an oil change (as mine did) and it gets filled to the top. This then goes out through the oil breather into the airflow and ends up clogging up the solenoid causing spiking and hesitation.