I have a 95 Cadillac DeVille, 170k, 4.9 engine and starting just a few days ago it has started to crank and crank but not start. Most of the time it starts up like it always has. Just sometimes it won't. I did a tune up in December, but I didn't include oxygen sensors. Wondered if this could be the issue? I have some codes from the computer but can't find any answer as to what they mean.
I have MANY codes like 128PD39 that I got from the PCM codes, but there are about 50. If anyone could help me here or steer me into the right direction it would be GREATLY appreciated.