I installed 2400 watt stereo system in car starter was bad replaced it along with sensors and coil pack what could have stereo knocked out

SOURCE: bonneville runs rough

ARE YOU SURE YOU NEEDED ALL OF THOSE THINGS?WHAT WAS THE ORIGINAL PROBLEM?BY SOME CHANCE WAS IT RUNNING ROUGH AND WERE HAVING A HARD STARTING PROBLEM TOO? DID ANYONY EVER CHECK YOUR EMMISSIONS?YOU WOULD BE AMAZED WHAT A CLOGGED CATALYTIC CONVERTER WOULD DO (MANY OF MY CUSTOMERS CAME IN WITH THAT ONE)

SOURCE: car wont start

I noticed you replace the crankshaft sensor, but not the CAMshaft sensor.
The Ignition module takes the input of both sensors to tell the coil when to energize.
This sensor should come up as an error code when you attach a obd reader.
Even if your light is not on - there may be a code. If it is not your vehicle originally, some people pull the bulb!

SOURCE: own a 1996 Grand AM GT 2.4 quad 4..manual...engine

engine missfire won't start

SOURCE: Code P0300 on a 2002 Pontiac GP with misfires on #

try switching one of the other coil packs with one of the bad ones. if this works then there you go. another way of telling if it is a coil pack is to disconnect the spark plug of the affected coil pack. if its a strong coil then you will hear the spark as well as see it. compare it to another plug boot that has the good spark. it sounds to me that it is a coil pack. i just changed one about 2 months ago with the same problem as yours.

SOURCE: 1999 Pontiac Grand Am is setting knock sensor

check all ground wires to these sensors. Even corrosion will cause codes to pop up