Why does my engine shake as I accelerate? on 2000 Buick LeSabre

2000 buick lesabre limited and ive had a tune up done, mass sensor, temp sensor, just had a new convertor put on yesterday and it still shakes viciously wen I pull off or excelerate, I can not figure this out. Somebody help me

Asked by for the 2000 Buick LeSabre
Ignition misfire, yes i read "tune up".
Thts possible cause after I got the convertor put on they said I need a tune up, but I had 1 done last month
2 more answers , 1 more comment
may not be engine. possible issue in drive links. have your drive train inspected.
any engine light on?i have seen this problem due to broken or bad engine mounts..
Yes, but tht may be because they did not erase the code after the convertor was put on! Could a crankshaft position sensor be a possible reason?