Engine codes, sensor & timing chain problems

I own a 2011 Grand Cherokee Laredo 3.6L
After check engine light, traction control and lightning bolts all lighting up, took
the Jeep into a mechanic. Told me a lot of sludge turned up in the motor, has
thrown the timing chain off. They did a oil change twice in hopes that would at
least get the vehicle running a little smother along with changing the cam shaft
sensor, but leaving me stating I’m gone to need a new motor. I have since
done an engine flush and two oil changes along with oil filters. Changes spark
plugs and cleaned the throttle body. Is it possible other sensors are
having issues and is keeping the Jeep from running properly? When I’m above
40+ mph it runs smooth, will not idle at a light. very frustrating.Any guidance/thoughts
would be appreciated, I do not have the funds to replace the motor (3.6L)
Thanks for any help

 

Welcome @FMGCL2011 ... any CEL right now? Did the mechanic state what codes were found/erased? Auto parts stores like Advance Auto can scan for codes. Post them here for internet diagnosis. Not convinced about needing a motor just yet but