What causes it to Surge

I have replace the EGR valve the purge solenoid the fuel pump the fuel filter air filter starter two power steering pumps alternator battery 3 new coils ignition module spark plugs and wires rack and pinion the front sway bar so if there's anything else it might be please let me know

Actually there is more it could be! .. That's the reason for the scan test is to FIND the problem instead of throwing parts at it... The information gathered during a FULL scan test is imperative for repairing these problems, take advantage of it! .. I don't mean run it by the parts store for some sorta so called test either... Full 'professional' scan test.. Save you money in the long run.. Posting all the possibilities is not going to help.. Good luck with it!