Cadillac Owners Forum banner

Hard Start/Bad Idle/bad miss under 2000 RPM codes P0300 P1101 P0301 in 2006 w/V8

2847 Views 7 Replies 5 Participants Last post by  tealBehindthwheel
Hello all!

I really need your help. My Northstar is sick far from home and I'm lost.

A few weeks ago I started getting the P1101 P0068 P0420 codes however performance and econ stayed the same so I assumed I needed a new throttle body or the software upgrade.

Two days ago, the tank was very close to "E" when I pulled into the gas station to fill up. As I stopped at the pump, the car ran a little ruff. I filled it up and it would start. After some working the peddle, I got it started but it wouldn't idle and had a very bad miss up to 2000 RPM. I drove about 50 miles at 60-70 MPH with near normal power and typical MPG but it didn't clear up.

After checking the forum and internet, I replace the spark plugs. I also put water around the intake and injectors but found no leaks. I then removed the intake to check for leaks and cracks. (didn't find any) I didn't have an injector tester however they hold pressure and didn't look too dirty. I Got it all back together and still have the hard start/hesitation/miss problem with the following codes P0300 P1101 P0301 and sometimes P0068 P0106.

Any thoughts? What else should I check before sending it to the dealer? Do you think it is related to running low on gas or just coincidence?

thank you very much in advance for your help

1 - 8 of 8 Posts
Hello, I just joined tonight and posted a similar problem. I have a 2005 STS, my codes stated that I needed ignition coils and injectors. I bought brand new injectors, and used old ignition coils that i saved from my original engine that blew. I still had the problem. I then bought a map sensor, a maf sensor, spark plugs, tightened the air intake bolts on the manifold, and still had the problem of stalling and no power. Last thing i recently did was buy brand new ignition coils and along with the ignition harness for both sides. Drives perfect now.
I replaced both coil packs and still have the same problem. :-(

What is the " ignition harness"? the one between the coil packs or between the coil pack and the ECU?

It's actually called the "module assembly" or "coil assembly", its the harness that holds the 4 ignition coils. I paid 159.00 for each side at rock auto. I bought ac delco, but they had two cheaper brands, airtex, and standard. Before my fix with the coil assembly, i replaced my injectors,spark plugs,map sensor,maf sensor, and tightened the bolts on the air intake. I should have just changed the coil assembly from the beginning.
Loose Intake Manifold Bolts usually don't even set a code unless they are so loose as to be merely sitting in their threads. They can almost be tightened to spec by finger (not even using ones whole hand!)
Sounds like it could be a MAF sensor. Has anyone tried that? The 420 code is a catalytic converter code. A clogged cat could cause problems like that too.
OEM paper air filter?

If not, wise up!


Nevermind, re-read thread ... ignition codes, right.
Hey there!

I'm having a similar problem with my sts4. I posted a thread about it. I went digging around a little bit and cleaned the air intake manifold and tightened the bolts. I also cleaned the injectors.

This is the sound my car is making when it idles. It is missing every now and then. At the end of the video i put the camera to the exhaust pipe and the sound it makes shows you when it misses. When i was recording the video, I saw the engine shutter every time it missed but you can't really see it in the video.

let me know what you think and hopefully we can exchange notes on this one.

1 - 8 of 8 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.