s10 loss of power hesitation codes po404 po452

[kolopedo]

1999 s10 4.3 auto 143k the symptoms no power hesitation and stuttering at various speeds i had a new fuel pump installed because the gauge wasnt working i also had a valve body installed cause the tranny was acting up which i thought was the culprit of the loss of power to start with but that wasnt the case i have changed plugs wires cap fuel filter checked fuel pressure was up to specs i also removed the o2 sensor to make sure it wasnt a clogged cat no change i also changed the gas cap.im getting a egr code po404 i cleaned the egr and im also getting a po452 code evap cntrl system pressure sensor low Here is my question is either code significant enough to cause the truck to run so terrible PS it seems to run a lot worse when its hot and when i fill the gas tank to the top

[Schrade]

Check for vacuum leaks.
Loping idle is vacuum leak. 30 year old lawnmower, or a new car on the lot. If it sucks air where it ain't supposed to, it lopes.

Brick on pedal, block TB arm, anything to get a STEADY idle. 1200rpms or so... Feed starting fluid spray, A LITTLE AT A TIME, EVERYWHERE. Rev increase is the leak.

In a tough spot to pinpoint? Light a book of matches, blow it out while the heads are burnin', and feed the smoke to the leak.