My engine is bogging on start up. :nervous:

History.

Ever since I got the 95 LS teg last yr with 93k miles I always noticed a jolting feeling upon start up in any stopped position (P, D, or N), which would go away after a few mins. As of 10 days ago upon start up the engine began to bog and jolt. By bog I mean, stuttering, hesitating, the exhaust going putt-putt. Would go away after a few revs and about 45-60 sec. This morning the bogging was so sever that I couldn't even drive off (even though I attemped) so I stopped a few houses down and let it idle (warm up) for over 6 mins before I was able to drive! But each time I started to slow to a stop it would bog again.

please help in finding out the problem.

No mods have been done to the car since last year. Only add ons: I/H/E
Current milage 123k, last oil change:122k
Thanks