05 5.7 hemi, on start up RPMs go to 4000 then drop to almost nothing and starts to diesel and surge

hardmam

i cleaned throttle body and replaced with what the owner got from salvage yard. no help. there are no trouble codes or broken or damaged wires. owner stated he went out to start one morning and been this way ever sense. motor was replaced 500 miles before this problem started

KCRam

Since this could be a number of vehicles with the 5.7... could you clarify what 2005 Dodge model it is?

Mr_Shiftright

Could be a whole bunch of things. Here's a very good article that gives you tips on proper diagnosis:

http://www.autoserviceprofessional.com/article/92420/The-dreaded-engine-surge