Here is his story:

So i was driving back to work after lunch today and i was on the interstate running about 65 and decided to lay into it a lil bit since there was no traffic around and i was runnin a bit behind schedule and as i do this i was in 4th gear everything is going fine, then all the sudden at WOT instead of hearing my SC screaming i hear a whoosh sound like a turbo spooling up and i have no power, the boost gauge maxes out to 20psi(god knows what it was really at since thats as high as it goes) and i have no clue what the hell just happened, no reduced power, car seems to run just fine as long as im not at WOT, still builds boost normally unless im at WOT...the only difference i am noticing is the whine seems to come on sooner like as im still pullin vacuum and there seems to be more a sucking sound when i start to build boost. I tried again tonight coming home from work thinking maybe it was just something with the weather since it was rather humid but still the same thing and i noticed a little bit of smoke behind me and it only does it when im at WOT, not under normal boost circumstances, this thing has me baffled and i have gone over every inch of the engine to see if i have a vacuum leak but i have not been able to see anything that is noticable so i turn to my brothers and sisters here at LCN to see if anyone out here has any ideas as to what it may be...so far this is the first problem i have really been stumped on and cannot come up with a solution so it really has me flustered, frustrated, and down right pissed off to the point i wanna get rid of the car.

My mods are 2.8, 60's, OTT h/e, injen, ingalls, 50 shot...no the nitrous was not on at anytime when this issue reared its ugly head, ported & plugged blower...i believe those are all the mods that have anything to do with the engine. Any help will be welcome otherwise its going to the dealer tomorrow or thursday and that means i wont be able to run at the track friday or get retuned but Light'balt Sat

any help will be nice, thanks guys

 

Could there be a problem with the boost control solenoid.
Or maybe the bypass valve actuator or related vacuum hoses or wires.

 

Muffler bearing!

 

Sounds like a plugged cat to me - boost gauge pinned, lack of power, and the whooosh at wot.

Wouldn't be the first one.....

 

Cat is clogged.

Why only a 50 shot? Get 2 of the big ones.

 

Agreed with others, symptoms sound like a clogged cat.

 

Do you need em by tonight?