Dont Know How To Title Problem????

[my98GST]

Alright, of a morning (usually around 65º in the summer and around 40º in winter) when i start my car and let it warm up a minute or two before i put it into gear to move, only in 2nd and 3rd gear at 3k right when it starts building boost, the turbo continues to spool but the boost gauge stops moving and then the car will catch and baugh down and not make any more power even though the turbo is still making 5-7lbs of boost... could someone please tell me whats going on with my car?

hope i explained it somewhat good enough for u guys to get what im trying to say

 

[oldman]

Check the plugs and wires then perform a boost leak test.