How do you reach and replace those 4 spark plugs by the fire wall on your 89 deVille?
It is a real pain in the neck. You have to jack the car up and get to them from underneath. The 2 closest to the passenger side are really tight so I hope you have small hands. You should be able to get to the 2 closest to the drivers side from the top. Take off the air cleaner assembly and slide some of the vacuum lines out of the way. Just be careful not to break any. The tools you will need are 2 extensions and a swivel so as to get around from underneath. I did mine 2 weeks ago and had grease up to my shoulders. Good luck. Almost forgot the most important thing. The engine has to be cool because you are right there at the exhaust manifold.