dude.
trust me. it isn't your egr valve.
you need to make sure everything is blocked off properly so you don't have any vacuum leaks. if there is a vacuum leak somewhere, or hell, even if the exhaust is leaking, it will make the car run poorly.

the symptoms you are describing are being caused by something else.
go through the list I told you
then move on to the other stuff
if you play attention to what you are doing, then you will find what your problem is

also, you are talking as though you have an automatic, have you checked the tranny out to make sure it isn't tweaking out. That could cause the symptoms you have talked about.

hell if could be something really simple like your TPS needs to be adjusted.

you only have 135 hp from the factory. between the drivetrain loss and the years of abuse and the miles that are on it, you probably have around 100 at the wheels. it isn't surprising that you can't break the rear wheels loose with your foot on the brake and the gas.