Changed Erg valve for reg Maint had no problem now rough idle and surging

What is your question?

Before that did complete timing belt actually did it twice to make sure done right and to make sure didn't jump tooth it was correct the code now reads po402 like I said thought it might have needed Erg but when starting it the engine feels like it gonna stall I have to pump the pedel then ride somewhat good when getting off highway it surges please please help me with my problem ohhh the car has 215ooo it ran greAt before timing belt change and never really needed erg but I did hoping it was problem I think could be a mix up or missing vacuum line !!