Engine codes and car stuttering....

I recently installed a set of smog legal headers on my 97' Trans Am. At the same time I replaced my plugs, wires, and coil. I am now getting two different trouble codes. P0300: Random Multiple Cylinder Misfire, and P1380: ABS Rough Road.....And at the same time my ABS INOP light comes on. The car stutters at low rpms especially if your in gear and just let it idle down the road.... Dont know if its the breaks pulsating or an actual misfire somwhere......I checked all plugs and wires for correct order and to be sure they were seated right. Im gonna check to see if anything is arcing anywhere.... Any info. on this would be great thanks.

Mine did that too... ended up being a combination of ignition module and fuel pump (before u do the fuel pump invest in a new fuel pump relay cuz most of the time it's the issue)... wierd huh?

the abs is a common problem among the 93 and up F-bodies for some reason... if im not mistakin it is the fuse that is under the hood that is the problem, i will double check on that too make sure and get back to you on it. As far as the misfire and such, had you not said you did all that work on it I would probly say that it was fuel related, but from what you said i think it is fire... check your timing and what not...it also sounds like it could be an O2 sensor... then i would go to the fuel filter and pump... but like "le12345671" said, check the relays too... good luck and let us know what happens when you get taht all checked out and we will go from there...
-Dusty

-also... there should be an egr line that ran from your intake maifold to your exaust manifold, (or vica verca, whatever the case is) you didnt damage that did you???