Saturn dies while driving even after purchasing new engine. Codes rpl headC HELP on 2000 Saturn LS2

I have replaced so many sensors than I can count. Even the fuel. Since I purchased the new (used) engine I thought surely the issue woudn't continue but it has. Not driving the car now. scared too. continues to stop in the middle of traffic. Dealers (Saturn no longer in my area) wants to replace what they did years before. So, any suggestions. I have had several mechanics look at the car, they have no idea what the problem is

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1 answer 1 comment
SATURNS A WEIRD CARS BUT A GM DEALER SHOULD BE ABLE TO REPAIR.DO YOU HAVE ANY CODES?
Not on hand but i did take it to the GM dealer the code read that we needed to replace the throttle body. I had already replaced this. I kind of don't trust them.