General Maintenance & Repairs Leaks | Squeaks | Clunks | Rattles | Grinds
Sponsored by:
Sponsored by: CARiD

Throwing a p0306 check it out

Thread Tools
 
Search this Thread
 
Old Sep 28, 2011 | 06:37 AM
  #1  
fire120ball's Avatar
Thread Starter
Staging Lane
 
Joined: Nov 2010
Posts: 98
Likes: 0
From: Livermore, CA
Default Throwing a p0306 check it out

So when i reset the code it runs great until the pcm relearns itself, I have so far changed my plugs out from my brand new NGK to my stockers, I also changed my MSD wires to the stockers, I have checked the spark and it looks good, I just now checked the voltage on the Fuel Injector and it was at 14.3. I also just listened to the injector with a screwdriver compared to the other injectors and it sounded like it was working. I had done a leak-down test when the motor was out, and it came out perfect, I also had the intake off for about 8 months and it went through basically nights in a barn. not direct weather, but condensation dust, etc.... Could the injector have gotten clogged? and How exactly do you change the Fuel injector too another cylinder to check if it is a injector? Guy's im at a loss, I searched everywhere for this.

Today I also had it ran by a friend at a auto shop with a scanner that scans all cylinders, and #1,5,6 were missing, but out of 20. 1=2 misses 5=1, and 6=14-17,18
I almost thinking it could be a crankshaft positioning sensor. Am I on the right track guys??

Last edited by fire120ball; Sep 28, 2011 at 06:41 AM. Reason: added info
Reply
Old Sep 29, 2011 | 03:03 PM
  #2  
fire120ball's Avatar
Thread Starter
Staging Lane
 
Joined: Nov 2010
Posts: 98
Likes: 0
From: Livermore, CA
Default

No one?
Reply
Old Sep 29, 2011 | 03:36 PM
  #3  
LS1WS6dreamer's Avatar
TECH Enthusiast
iTrader: (1)
 
Joined: Jun 2010
Posts: 575
Likes: 0
From: Arkansas
Default

So if you unplug the battery and everything resets you can drive the car fine or a while?

When my 02 sensor started going bad I would get the SES blinking at me. Multiple misfires or some **** when I ran the code. Did it off and on and would literally make the car surge and jerk, but it only did this after driving it a while.
Replaced 02 sensor and everything was fine.

I wouldn't think that a injector would be clogged and then when you unplug the battery and plug it back in it runs fine for a while. I would guess a clogged injector would stay clogged. Not intermittent
However, the injector could be going bad. Not necessarily clogged.

Coil pack harness backwards???

Sorry I couldn't help much. I am just trying to throw and idea or two out there. Stimulate your thinking; sometimes it helps people figure stuff out.
Reply
Old Sep 29, 2011 | 03:36 PM
  #4  
GMRL's Avatar
TECH Enthusiast
20 Year Member
Liked
Loved
Community Favorite
 
Joined: Sep 2005
Posts: 503
Likes: 54
From: TX
Default

I went through the same thing a while back in my 02. I pulled the rail off, and cleaned it and the injectors individualy in a parts washer. Hasn't done it since, its been about 20k miles.
Weird thing is that it would do it intermittently. Since the regulator is in the module in the tank, debris goes all the way to the injectors and stays there.
Reply
Old Sep 29, 2011 | 04:49 PM
  #5  
fire120ball's Avatar
Thread Starter
Staging Lane
 
Joined: Nov 2010
Posts: 98
Likes: 0
From: Livermore, CA
Default

I'm thinking they might be clogged so when I first start my car it starts to run rich so its putting more gasoline into the cylinder so once it leans out it is not getting enough fuel? I will take my injectors out and clean them, thanks guys
Reply
Old Sep 29, 2011 | 05:46 PM
  #6  
Darkman's Avatar
TECH Addict
iTrader: (2)
 
Joined: Apr 2009
Posts: 2,167
Likes: 6
From: Spring, Texas
Default

See attached.
Attached Files
File Type: pdf
P0306.pdf (98.4 KB, 537 views)
Reply
Old Oct 6, 2011 | 11:51 PM
  #7  
fire120ball's Avatar
Thread Starter
Staging Lane
 
Joined: Nov 2010
Posts: 98
Likes: 0
From: Livermore, CA
Default

Update,
I pulled the injectors all out and hit them with some carb cleaner and they all looked like they were in good shape, descreened my MAF at the same time. Put her all back together and the code is still on but its not surging like before.

Next thing im going to do is switch the coil packs, see if this helps. and do a compression check at the same time... if this fails I will be thinking its the crankshaft positioning sensor or the 02's.

I will swap the 02's to different sides to see if I get any affect... And if this fails... I need you guys! I know my valve springs are not broken, my lifter? brand new pushrods. I just want her to run good again guys!

Last edited by fire120ball; Oct 6, 2011 at 11:56 PM.
Reply
Old Oct 7, 2011 | 11:26 AM
  #8  
jimmyblue's Avatar
Moderator
iTrader: (11)
 
Joined: Mar 2002
Posts: 12,604
Likes: 7
From: East Central Florida
Default

I think this is an injector imbalance. If you have four of them
and one shoots lean, the fuel trims will pull the bank rich to
make up for that (running crappy, and the lean one will still
perhaps misfire).

On the other hand if one's a drooler, the bank will pull leaner
and the other three ought to be showing elevated misfires.

The reset making it run better temporarily means something
like this is going on. You might swap injector 6 for 4 and see
if the problem moves. If it doesn't then you have to look at
single runner vacuum leak or a spark path problem. Misfires
of any sort can fool the O2s into mistrimming, including a
spark (not intake AFR) problem.
Reply
LS1 Tech Stories

The Best V8 Stories One Small Block at Time

story-0

Amazing '71 Camaro Restomod Is Modern Muscle Car Under the Skin

 Verdad Gallardo
story-1

6 Common C5 Corvette Failures and What's Involved In Repairing Them

 Pouria Savadkouei
story-2

Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph

 Verdad Gallardo
story-3

Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked

 Pouria Savadkouei
story-4

Top 10 Most Powerful Chevy Trucks Ever Made!

 
story-5

Hennessey's New Supercharged Silverado ZR2 Has 700 HP

 Verdad Gallardo
story-6

Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes

 Verdad Gallardo
story-7

Awesome K5 Blazer Restomod Comes With C7 Corvette Power

 Verdad Gallardo
story-8

10 Camaros You Should Never Buy

 
story-9

10 LS Engine Myths That Refuse to Die

 Verdad Gallardo
Old Oct 7, 2011 | 09:22 PM
  #9  
fire120ball's Avatar
Thread Starter
Staging Lane
 
Joined: Nov 2010
Posts: 98
Likes: 0
From: Livermore, CA
Default

Jimmy, I did switch the two but I still have a mis on 6... I changed up the coil packs today with no luck... Still p0306..... I'm at a loss, I plan on doing a compression test (even though I did a leak down when my motor was out and all came up perfect...) If the compression tests tell me nothing I will proceed to swap the 02's for sides... I need help...
Reply
Old Oct 7, 2011 | 09:46 PM
  #10  
JaYZeig's Avatar
TECH Enthusiast
iTrader: (11)
 
Joined: Apr 2010
Posts: 599
Likes: 1
From: plainfield, il
Default

so, if youve tried all the simple stuff, and its still pinpointed on cyl. 6...its gotta be a mechanical issue, broken/cracked valvespring, loose rocker, bent pushrod, or even slightly collapsed lifter. youll still get compression on that cyl and have minimal leakdown..somthing id start looking into.its not hard to pull the valvecover and take a look.
Reply
Old Oct 10, 2011 | 03:35 AM
  #11  
fire120ball's Avatar
Thread Starter
Staging Lane
 
Joined: Nov 2010
Posts: 98
Likes: 0
From: Livermore, CA
Default

Its not a loose rocker, nor bent pushrod (Brand new pushrods installed myself), possiblity of a lifter, and it is not a broken valve spring. I'm almost thinking a crankshaft positioning sensor?! Does anyone have any experience replacing one of these? And if so where is it located? Thanks guys....
Reply
Old Oct 10, 2011 | 03:39 AM
  #12  
lemons12's Avatar
TECH Senior Member
iTrader: (71)
 
Joined: Jul 2007
Posts: 11,088
Likes: 2
From: Winchester, TN
Default

Skimmed thread, have you ruled out o2s? Very common.

FWIW, I have 2 if needed.

Is it loaded up/back firing at all? Does the idle act strange at all?
Reply




All times are GMT -5. The time now is 11:04 PM.

story-0
Amazing '71 Camaro Restomod Is Modern Muscle Car Under the Skin

Slideshow: This heavily modified 1971 Camaro mixes classic muscle car styling with a fifth-generation Camaro interior and modern LS3 power.

By Verdad Gallardo | 2026-05-12 18:06:42


VIEW MORE
story-1
6 Common C5 Corvette Failures and What's Involved In Repairing Them

Slideshow: From wobbling harmonic balancers to failed EBCMs, these are the issues that define long-term C5 ownership and what repairs typically involve.

By Pouria Savadkouei | 2026-05-07 18:44:57


VIEW MORE
story-2
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph

Slideshow: A modern Camaro transformed into a retro icon, this limited-run "Bandit" build blends nostalgia with brute force in a way few revivals manage.

By Verdad Gallardo | 2026-04-21 13:57:02


VIEW MORE
story-3
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked

Slideshow: Cadillac didn't just crash the high-performance luxury vehicle party, it showed up loud, supercharged, and occasionally a little unhinged...

By Pouria Savadkouei | 2026-04-16 10:05:15


VIEW MORE
story-4
Top 10 Most Powerful Chevy Trucks Ever Made!

Slideshow: Top ten most powerful Chevy trucks ever made

By | 2026-03-25 09:22:26


VIEW MORE
story-5
Hennessey's New Supercharged Silverado ZR2 Has 700 HP

Slideshow: Hennessey has turned the Silverado ZR2 into a 700-hp off-road monster with supercharged V8 power and a limited production run.

By Verdad Gallardo | 2026-03-24 18:57:52


VIEW MORE
story-6
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes

Slideshow: A one-off sports car that looks like a vintage Italian exotic-but hides a C6 Corvette underneath-just sold for the price of a new mid-engine Corvette.

By Verdad Gallardo | 2026-03-23 18:53:41


VIEW MORE
story-7
Awesome K5 Blazer Restomod Comes With C7 Corvette Power

Slideshow: A heavily reworked 1972 K5 Blazer swaps its off-road roots for a low-slung street-focused build with modern V8 power.

By Verdad Gallardo | 2026-03-09 18:08:45


VIEW MORE
story-8
10 Camaros You Should Never Buy

Slideshow: There are thousands of used Camaros on the market but we think you should avoid these 10

By | 2026-02-17 17:09:30


VIEW MORE
story-9
10 LS Engine Myths That Refuse to Die

Slideshows: Which one of these myths do you believe?

By Verdad Gallardo | 2026-01-28 18:10:11


VIEW MORE