turbo problems

hey guys, i once again call on ur expertease for my be loved volvo. ok, well i live in VA and its been getting mightey cold around latley and my turbo seems to love it. hard pull, no lag. now, sometimes when crusing (dont really know the speeds) i go to floor my car to listen to the turbo spool up, everything is fine upto about 5 psi, after 5 psi it begins to sound muffled and my car starts to hesatate no jerking or anything wild, it kinda just stops going after 5 psi, but the weird thing is my boost guage seems to be reading normal psi, btu the "umth" is no tthere until i left go off the gas then go WOT again. When the turbo spools up its sounds great till 5 psi, liek i said, then after 5 psi, i hear the turbo get muffled kinda, but the sound continues to build higer like normall, only sounds really "muffled". its weird. it only doe sthis in high gears, no problemes in 1st, 2nd. SO any ideas on this problem would be great btw, i have a 87 740 ti------maybee the turbo is going? PLEASE help, this is really bothering me----THX a million

Sounds like a clogged cat to me, if your power and turbo stop pushing after 5PSI or so you might have a clogged cat or something. Try gutting the cat and see what happens.

well just one thing, i have no cat, juat a str8 pipe, and no mufflers. one more thing the boost continues to build after 5 psi, just stays muffled.well thx yall---------stumped volvolover----------just onb emore question-
for my car, im intersted in a new turbo. i have the mitsu now, bu tim looking for something bad ass, not over kill but, just kinda kill. i would liek one with no cbv or bov so i could install a bov and get that great sound. thx----

Check your hoses and piping for loose clamps and the hoses for splits. How old are your plugs/wires?

Late