I noticed today that my boost pressure had dropped from 20 psi to 9 psi (via boost gauge). There was obviously a noticable drop in power as the turbo didn't seem to be fully spooling up (in any gear). Searched the forums and it seems a few people have had similar problems. After restarting engine, boost pressure is back to 20 psi and everything is running fine. At no time were there any warning lights. My Vrs has 18,000 mls on the clock, run on optimax but this happened when on 95ron...mods below.

I have checked all the hoses and all seem to be tightly fitted. I recently had the dump valve (007p) serviced and changed the spring from green(soft) to yellow (hard), I also had a samco tip fitted. Could either of these have contributed to this temporary loss of boost as this is the first time this has happened.

In veiw of the above, what are everyones opinions of how to permanently rectify this problem? Head gasket...MAF...throttle bodies?

isnt the 4bar software only really designed for 98ron or over?

Almost certainly MAF - does seem to be a major design fault on all Skodas. The recovery after you switched off/on is the clue.

I had this exact same problem. Dealer replaced boost hoses (search the forum for lower boost hose and 17705), diverter (dump) valve, and eventually throttle body. The throttle body replacement appears (touch wood) to have cured it.

Not had it since the weekend but it will almost certainly appear again. Is replacing the throttle bodies a big job? I ask because I've got it booked in for some warrenty work already (rad mounts) whihc is gonna take half a day apparently!

I had this exact same problem. Dealer replaced boost hoses (search the forum for lower boost hose and 17705), diverter (dump) valve, and eventually throttle body. The throttle body replacement appears (touch wood) to have cured it.

If that doesnt then the next step is to change the air temp sensor.

The ignition on/off curing the fault indicates its an overboost fault. These are usually caused by a leak. Prime target as mentioned elsewhere is the pip that goes from the i/c pipe under the o/s/f arch to the turbo. It has been modded to a twin lip seal.

Not had it since the weekend but it will almost certainly appear again. Is replacing the throttle bodies a big job? I ask because I've got it booked in for some warrenty work already (rad mounts) whihc is gonna take half a day apparently!

Didn't take them long. But that was on about the fifth visit. I knew the dealers so well I ended up getting the dealer principal's Octy II 2.0FSI Estate as a courtesy car on one trip.

They will replace everything else before they start on the throttle body though, one bit per trip, as the TB isn't cheap.