Just Bought PLEASE help

I just bought my 97 GT. Right now in the process of the usual maintenance, and man does it need it. Oil hadn't been changed for who know's how many 1000's of miles. Fuel filter, pcv, plugs, threw a k&n in it. My problem is...I broke one of the sparkplug wires, so I went and picked up a new set of wires all around. Since I changed those out the service engine soon light is now on. Made sure all vaccuum lines were connected etc. Anything I touched I made sure it was back to the way it was. What might have caused this. Any first quick fixes I could try? Also, there is a clunking sound in the rear. Mostly when I'm backing up, or going over small bumps slowly. Any ideas? Struts, bushings, something else?

I just bought my 97 GT. Right now in the process of the usual maintenance, and man does it need it. Oil hadn't been changed for who know's how many 1000's of miles. Fuel filter, pcv, plugs, threw a k&n in it. My problem is...I broke one of the sparkplug wires, so I went and picked up a new set of wires all around. Since I changed those out the service engine soon light is now on. Made sure all vaccuum lines were connected etc. Anything I touched I made sure it was back to the way it was. What might have caused this. Any first quick fixes I could try? Also, there is a clunking sound in the rear. Mostly when I'm backing up, or going over small bumps slowly. Any ideas? Struts, bushings, something else?

What brand of wires? The SII 3800 works best with the AC Delco Premium Silicone 7mm wires.

Get it scanned since the SES light is on.

Noise sounds like upper strut mounts/load bearing.

Some xact fit junk. The only thing they had for now. I wanted the AC's, so I'll go and order those. Put in the AC Delco iridium plugs. Haven't jacked the car up to look at the rear end. Weekend project.

Some xact fit junk. The only thing they had for now. I wanted the AC's, so I'll go and order those. Put in the AC Delco iridium plugs. Haven't jacked the car up to look at the rear end. Weekend project.

Sounds good. They are the best. Good luck!