i have a 2.8 pulley and was hitting 18lb of boost at 7000 rpm
last week i started hitting 20lb plus at 5000-6000 rpm and car is running horrible
any one know why

 

It could be 2 things,clogged cat or ic pump isn't working.

 

What he said.

Still on stock downpipe and cat? Probably the kitty got a hairball.

 

i went back to stock and its still hitting 15 plus
i guess its going to the shop

 

If the car is running like ****, it is a clogged cat.

 

^^^^ what he said. change cat and it will probably be better

 

new cat today dealer covered it

 

i believe your mods are just too much for a stock cat to handle, i didnt see if you were stock header/dp, if you are next time your cat gets messed up id suggest going with an aftermarket highflow cat.

edit: also if you are switching to a better flowing exhaust your boost might be a little lower, but the car will be running the boost more efficiently creating more power.