P0301 Cadillac Code - Cylinder 1 Misfire Detected

My Cadillac CTS 2005 is misfiring. Changed spark plugs and coils. I'm still getting code p0301.

Is there excessive smoke, is the engine running rough? Have you overheated the engine lately?

I'm a few years late to the thread but I have the same problems on my 08 cts. No overheating but it has a ruff idle. & it started to squeak

Have you replaced any parts yet? The ignition coil and/or spark plugs are the most common problem for the P0301 code, but if you have already replaced those parts, then you may have a problem with the fuel injector.

Yeah, those were the first things I replaced. I bought a fuel injector too but didn't change it because I didn't want to keep throwing money into the car without knowing the cause first. So I had a mechanic see it and he said I had no compression in cylinder one. Based on that information he suggested a new engine. I don't know if that's a good fix so I'll look for a second opinion. Anyways, thanks for the help.

Had the same issue with P0305 and Mechanic told me new engine needed $4000. Two years later that issue was restored now I am dealing with p0301. Changed coil pack, sparkplugs, fuel injectors, fuel filter. What left I will have to do vacuum leak, fuel pressure before I go too far.

What model and year is your vehicle? your next step is to perform a cylinder compression test

Cadillac cts 05, v6. 3.5. It got 252000 still drives strong. She loves speed. If I delete the code it won't come up again as long as I didn't stop. If I delete the code and leave it on idle she doesn't like that and check engine would be flashing. I have raise rpm over 800 before it goes away. It idles between 500 and 600rpm rough and over 800 rpm smooth .

I was looking for answers on this P0301 code and started researching DIY info. I ran across a video on how to change plugs and coil packs on a 3.6L V6 Cadillac STS VVT motor (2007). Almost as an after thought the guy on the video mentioned how years ago he found out that having a low oil condition doesn't get enough oil to the timing chains and that it gave him this code. I thought why wouldn't you get a low oil or check oil level indication first before any trouble like this ? There is no good excuse for why I hadn't checked my oil in a while so I won't make one up but I added oil, ran this thing and it stopped acting just how it had with the P0301 code. All the misfiring, jerking, bad acceleration and fear my timing chain had gone bad was gone. Keeping my fingers crossed that my issue is resolved with simply adding oil while I keep an eye on it for a few days.

Thank you for sharing and I hope that fixes the problem.