I have had my number four coil pack read bad twice I put a new one in and it didn't fix so I ended up going thru four new ones none worked till I switched number four with number three then it was fine for about six months now same thing any suggestion why this is happing

If it is your coil pack, you should be getting a misfire code for a specific cylinder.
After you have that info, change the coil pack from the bad cylinder to one that is known to be good, drive the car around for a while and check your code again.
IF the code moved to the same cylinder as the coil pack, then you know that specific coil pack is bad.
IF it stays on the same cylinder, then you know that it has something to do with the wiring or something else pertaining to that specific cylinder.

Start with that and let us know what you came up with.

OK I have now switched coil pack from cylinder 4 which is the one reading bad with cylinder 3 thought I'd would be easier to replace also if out did fix but that did not fix the to problem so I tried switching with other cylinders still no good I've got that problem plus I now have another one the car has almost no exhaust coming from tail pipe and bogs completely down then it's really hard to start it is trying to blow oil out of dip stick and the oil fill cap spot I'm hoping it's the converters so if you have time and experience for this I could use allot of advise

The switching of the coil packs wasn't to fix the issue, it was to determine if the issue was caused by the coil packs or some other wiring issue.

OK and no it didn't change it still cylinder four so prob is a writing prob any suggestions on where to start looking for the problem or do you think it would be in the computer

I don't think that it is the ecu (computer) because you most likely will get other random codes if that's the case.

Some of the wiring are very fragile as well as some of the connectors.
Get a multimeter and search for continuity among the wires.