Boost problems???

[1quicksix]

Okay guys i just got a 87 gn w/ 16,000 miles its a all original car . . but its like the car just wont build up the boost like its suppose to . . if you power brake it, the car wont boost up and brake the wheels loose like it should seems like it just doesnt have any low end power. . if you powerbrake it for what seems like ever it slowly (very slowly) builds up boost and when it reaches somewhere around 8 pounds it just takes off and shoots right up to 15 like and should . . any one know what might be wrong . . changed the boost seloniod and wastegate actuator . . and the car does seem to run right once the boost gets up just seems to have alot of lag

 

[QUIP'6']

check for ezhaust leak on driver side header between 3 and 5 cylinder. an exhaust leak pre turbo will cause slow spool do you have a scanmaster on it if not GET ONE !!!!!!!!!!!!! if so check and see what your blm's are if they are maxed at 150 then your running lean and your computor is telling it the car to dump more fuel to compensate for the lean condition which in turn will cause it to run pig rich also when your brake boosting it is there black smoke poring out the tail pipes? another thing is to get a chip off of eric marshal they are the best i will sell you one the one i have is for stock injectors and 93 octane will idle like nothing else i stepped up to 43# injectors so i cant use it . $45.00 shipped to you they are 75 new. this chip is only 6 months old