ok to start off what transmission is in the 98 camaro automatic just incase i need to look for anew one.

next this is my problem ok starting off sometime when i go from reverse to drive it makes a loud popping sound not sure if its from the trans but sound slike it.
next is when my car is at wot and going from 2nd to 3rd gear it will hit the rev limiter and tag off of it for a sec or so then shift i just dont know whats going on i onlyhave basic mods lid and exhaust. is the trans shot or what?

 

Give us a few more details about the car like mileage. What's the rear gear ratio. When was the last time you checked out the U-joints? These are just examples.

 

i bought the car a year ago it has 118k miles he said the trans was rebuild like 30 or 40k miles ago the gears r the stock ones i think. iv never checked the ujoints tho

 

If its just tagging the rev momentarily then shifts and the shift is relativley firm when it does. I would say possibly a tuning issue. When power adders are installed even just bolt ons it can be nessesary to reset shift point to compensate.
On the clunk I would look at u joints, trans mount , torque arm bushings.

 

i thought that too at first but im not so sure its like it slips up to the rev limiter and tags it pretty bad then shifts i mean when it shifts its like the car then pulls again but will not pull at all while its on the limiter