2002 Dodge Intrepid

I bought a 2002 Dodge intrepid SE 2.7L and not even a week went by when the car engine failed due to oil sludge. I bought an engine at a junkyard and they installed it at the same place. The car works fine until it reaches 2500 RPM, then it jerks. It does it weather in gear or in Park if pushed to 2500 RPMs. Also sometimes it won't turn on on first or 2nd try. I found out from another mechaninc that they used a 1998, or 1999 2.7L engine. It appears to be a timing issue but timing has been set three times, also cran and cam sensor replaced, and reprogrammed car's computer, none of it works. Is this engine not compatible?