Stumbling Issues

[UpRise]

I have a 2001 protege LX with the 2.0 engine. Recently I have had engine stumbling under throttle. The spark plugs are okay, as are the connections on the battery terminals. It just started as of recently and I haven't made any changes to the car recently, although i do have an aftermarket intake, exhaust and cat-delete. Any other ideas as to what it could be?

[lasermp5]

clogged egr valve?

[UpRise]

clogged egr valve?
I'll go ahead and check that out tomorrow
edit: checked egr, nothing wrong with that, now stumbling all the time, like one cylinder is running on half power, i think it may be a valve leak or broken valve spring