: Plugs and Plug Wires

04-27-04, 09:00 PM
As a modestly competent Shadetree mechanic, I need to change the plugs and wires on 99 Sedan Deville w/N* engine. What is the best way to attack it? What has to be pulled from the engine to gain access? Where is the best spot to shop for plugs and plug wires?

Thanks for the response,


04-28-04, 12:10 PM
I just did my plugs and wires on my 99 Eldorado a few weeks back. I don't think the Sedan DeVille should be too much different...

I bought my wires and plugs at the my local Ac/Delco parts dealer and kept everything ac/delco. Total cost was around $200. While I was there, I also got a new PCV valve, new air filter, etc., etc..

The actual job is pretty straightforward except for changing out the wires.

Take off the plastic dust cover (4 13 mm nuts) but be aware that there are long skinny studs underneath that screw into the block. If the nut on top sticks, it will make the whole thing turn.. as you loosen up the nuts, you should be able to lift the dust cover slightly and then grab the stud with a vicegrip and then take the nut off.

Take the cover off and you'll see the fuel rail with the wires and such going to their plugs. The plug holes are DEEP. If you use a standard plug socket with a rubber insert, when you put the plugs back in, getting the socket off the newly installed plug will be tricky.

The only other thing I ran into was when I changed out the wires, I had to take the ignition module off to get to the back plugs easier. This will cause several codes to be generated. Make sure you rout all the wires neatly and then just put it all back together.

Note - there is a ground wire UNDER one of the bolts on the ignition module - don't forget to put it back in place when you re-assemble. Also, it's a good time to clean it up to make good contact again.

Just be methodical and work carefully and the job will go easy. don't RUSH it.

One thing you may consider since you'll have the top of the engine exposed anyways - take off the air cleaner and then the throttle body. Use some carb cleaner and a toothbrush and clean the hell out of the intake and the valve so that it shines. Then re-assemble. Before turning the car over, disconnect the negative battery lead for 30 seconds to reset the throttle sensor and then you sohuld be good to go.

good luck!

04-29-04, 01:10 PM
Check out Rockauto.com. I got all delco parts and I think I paid around $150 shipped for the wires and plugs. I just looked it up: $136.99 plus shipping ($10 or so) for the plugs and wires. This is the best deal you are going to find for genuine GM parts. Believe me, I looked everywhere.