Sounds like it's time to put a compression tester on it. Start looking inside for the problem.

 

I had already checked compresion, and it was good.
The map sensor was broke at the connector and not working. replaced it and now it runs smooth . but I am still wondering about the converter. It still sounds a little lowd .

 

ck the exhuast bolts, you may have some loose. and give it a good road test. the converter should be alright.