Can anyone tell me what engine is in the 05 STS, a friend of mine says that it was missing badly his mechanic replaced a coil the check engine light went out and after about one hour the same symptoms returned, I forgot that the STS came in rear wheel drive do they also have the NORTHSTAR engine, I ask because in the DeVille there were two coils one in each of the valve covers, so I was wondering if the STS also had the same coil setup as the DeVille….Thanks in advance for any help...JohnB

 

The STS is a rear wheel drive model. They did not come with the same front wheel drive setup as the DeVille.

Now as for engine size, I know they offered at least three different engines in the STS. One was a 3.6 Direct Injection V-6...that's the one that I have in my 06 STS and it has six coil packs, one for each spark plug. At one time or another, I have replaced four of them. The first to give out was number 5 and for some reason it has gone out twice, Still can't really complain though since I do have 235,999 miles one it.