Computer problem
2004 Chrysler PT Cruiser 4 cyl Front Wheel Drive Manual 68,000 miles

Started with check engine light , next they said I had a week cyclinder , lifter was dropping , I had them change them all , now the computer wont reset , it failed smog (OBD) Catalyst/02 monitor , they said I needed to drive in fourth gear at 50 mph for a few minutes at a time ,well Ive gone over 200 miles at this speed with nothing on in the car , it did'nt work and now they have sent me away saying they will look into it...Any help would be great..thanks gene