I've had code 0304 and 0707 for about 3 weeks now, since the rear oxygen sensor (0707) doesn't do anything I've been slow in replacing it since I got the part a week or two again.

Anyways, that's not my real problem, I just replaced the spark plugs, followed the instructions on vqpower (I put in NGK Coppers), started the car everything was fine, after driving it for 30 minutes I decided to check the check engine codes just to be sure everything was ok and I just got a new code 0302, EGR valve. Now could this be caused by me replacing the spark plugs? Or doing something incorrectly? I don't think I've had the code before since I resetted the ECU a couple of times a week ago, in between trips, to make sure that I only had the 0304 and 0707 codes.

Any ideas would be appreciated. BTW it's a 95 GLE with 85 000 miles.

 

Nope. Just a coincidence.

Most likely you need to clean out the EGR port and the EGR guide tube that runs from the EGR valve to the plenum. Both of these parts/areas are prone to clogging up with carbon deposits and trigger the 0302 code you are getting.

 

your plugs dont have enythink to do with EGR

 

Great, that's good to know. I'll replace the Rear 02 sensor this weekend and I'll see if the maybe the EGR code goes away. Can the two be possibly related?

 

A collection of carbon buildup on the EGR and O2 sensors. Maybe do some seafoam before you change the sensors

 

Nope... it's got nothing to do with the rear o2 sensor or any o2 sensor for that matter... clean out the 2 areas I mentioned, reset the code and I'll bet you the code will go away (the 0302).