1st gear boost WOT Cat or
 

In the process of checking the car over for the potential next owner. The car isn't driven much (just run every weekend) and is really never abused, just the occasional third gear "show off" pass up here in the boonies. I always start the car 10 minutes before I drive it, so it was fully warmed up this morning. When I floored it in first gear from a rolling start, I didn't get full boost like the second turbo didn't spool and it was doggy, second gear was off to the races. I have always gotten 10-8-10 in third gear, maybe 10-8-10.5 with the downpipe. The only real mod is the HKS downpipe. Is is more likely a vacuum line (all replaced and tied up), one of the solenoids under the UIM, or the main cat? Or is it just the nature of the beast.

I am not really sure how long it might have done this because I don't drive it hard, just the occasional run to the redline cause its good for it.

http://www.autosportracetech.com/RX-...leshooting.htm

Check the Turbo Control/Actuator section:

Do I need to pull the turbos to get at the turbo control actuator? Could it just be a vacuum or boost line to it?

The actuator is down alongside the oil pan. No need to pull the turbos, although the nuts holding the actuator take a little bit of patience.

Definitely check the vacuum lines for a loose connection.

The problem is usually the solenoids, not the actuator. Pull the UIM and you can access the solenoids.

Well, I pulled the UIM on my S5 about 100 times for different things. Time to get some balls. Whatever it takes to keep it out of the hands of a piston mechanic.

The connector on the Y-pipe was loose on the bottom. Replaced the clamp and first gear boost magically appeared again. No figure. I went through and checked everything again anyways. I actually found a vacuum line without a zip on it, close one. Thanks for all the help!