Misfire Diagnosis

TB_n00b

Original poster
Member
Dec 19, 2011
121
Queens, NY
Hey all. I'm in the process of looking into a persistent CEL that appeared to be related to outside temps (usually appeared under 40 and went away over 40) but now I am getting is consistently and am observing significant misfires (car shaking side to side on cold start). The misfire usually clears up after about 30 seconds and the engine smooths out.

I checked the codes with Torque and found P0171 - Too lean bank 1, P0300 - random/mult misfire & P0014 - 'B' Camshaft Position - Timing Over-Advanced or System Performance (Bank 1). I have done the camshaft solenoid replacement ~ 1.5 year ago. I also did a spark plug change, a short mileage oil change with Seafoam to try to clean out some much last summer and cleaned the TB and MAF at the same time. Incidentally, when I drained the oil I only pulled out about 4 quarts. Change prior to my effort was done by my usual shop when I had the car inspected.

I have a new coil pack and will be doing the swap one at a time method to attempt to isolate a bad coil pack. I'll also do a TB clean again if it warrants it.

My question is, based on my seeing and feeling the car physically shake on a start, does that point to something more significant than just a single bad coil pack?

TIA.
 

Mooseman

Moderator
Dec 4, 2011
25,257
Ottawa, ON
Without a hard code giving which cylinder is misfiring, I doubt a coil is the issue. The lean code may point to the actual cause if it's leaking so much that it's misfiring, that would affect all cylinders. Fix that first and go from there. Especially look at the intake manifold bolts. Use carb cleaner to try and find the vacuum leak.


For the P0014, it could be the CPAS again if you used an aftermarket part, especially Dorman which are known junk. Use only ACDelco or Delphi.
 
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mrrsm

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The P0171 lean behavior and the random multiple P0300 are tied together, so your Coils are probably fine. The troublesome P0014 could mean that you really need to pull the CPAS once again and do a good Engine Flush... One Quart mixed in with CHEAP Organic Motor Oil with a CHEAP Oil Filter and allow the vehicle to IDLE for around 5 or so minutes without raising the Engine RPM. Then Drain out that Flushing Oil and change the Oil and Filter over to Mobil1 products. Oil AND Filter.

If your vehicle sports a SAIS system... This video is very helpful in figuring out whether you need to change the SAIS Solenoid on the passenger side of the Engine as...if it sticks open and runs beyond the normal amount of time without closing... It will induce an excess amount of air into the system that will cause the O2 sensors to read Lean:

 

TB_n00b

Original poster
Member
Dec 19, 2011
121
Queens, NY
Thanks. I'll take a look for vacuum leaks, check the TB, make sure all hoses are connected and tight and if all that fails, maybe pull the CPAS. I used an AC Delco replacement for that last year. Screen were all gone.

I can't imagine I need to do another oil flush. I didn't let it sit running at idle for 5 minutes but drove it for about 10 minutes and went right to the change after it cooled down a bit. Maybe it's a leaking pump like in the video. The CEL is never on right away after a reset. It's always on after a few minutes.
 

TB_n00b

Original poster
Member
Dec 19, 2011
121
Queens, NY
Popped the hood today. Oh boy...

Checked the TB. Clean. Made sure everything was tight. So, yes, the CPAS was gunked up. Middle screen had a thick layer of gunk. pulled the o-ring, pulled the retention spring and carefully cleaned the gunk off with TB cleaner. Clean for now.

Separately I found something worse. I popped the oil cap to get some oil to apply to the cpas o-ring and there was a whole bunch of milky white stuff in the cap, in the fill hole and even on the dip stick. hows the coolant level you might be inclined to ask...oh pretty low. like the resevoir was near empty. Also, when I pulled the resonator, a good amount of water came out the crankcase vent hose and resonator itself.i

suspect i have less time with this car than I thought.

20180218_124726.jpg20180218_125304.jpg20180218_125313.jpg20180218_133455.jpg20180218_135802.jpg20180218_140236.jpg
 

Mooseman

Moderator
Dec 4, 2011
25,257
Ottawa, ON
You did good cleaning out the TB and CPAS. The milky crap under the cap is condensation and is considered normal, especially in winter. The water in the resonator as well. A flush and an oil change might not be a bad idea.

How's it running now?
 
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TB_n00b

Original poster
Member
Dec 19, 2011
121
Queens, NY
You did good cleaning out the TB and CPAS. The milky crap under the cap is condensation and is considered normal, especially in winter. The water in the resonator as well. A flush and an oil change might not be a bad idea.

How's it running now?

Still have a p0171 so maybe i need to go about changing the SAIS but it runs normally anyway.

I guess I can see how the coolant level does the next few weeks.
 

mrrsm

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Oct 22, 2015
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Before you Change The SAIS Solenoid... Hearken back to @Mooseman's suggestion about seeking out those Vacuum Leaks First...and take a look at THIS Video for a different solution:

 
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TB_n00b

Original poster
Member
Dec 19, 2011
121
Queens, NY
Yeah I'll be doing the vacuum check first. Will check out that video at lunch but I only suffered rough idle symptoms during cold start up until the exhaust pump runs through its cycle. No performance issues when at running temp and during normal driving.
 

Mooseman

Moderator
Dec 4, 2011
25,257
Ottawa, ON
And if it happens to be the SAIS valve, I'd just delete said valve, block off the port using a block off plate from an '02-'03 (or make your own) and get the codes deleted via a tune at Lime-swap.com (@limequat ). Apart from the valve, the pump has also been known to fail. Also get other stuff modified like fan codes and such.
 
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TB_n00b

Original poster
Member
Dec 19, 2011
121
Queens, NY
Any thoughts on how the temperature might play into this and if the CEL being related to colder temps might point me to a certain diagnosis?

Yesterday was warm, in the 50s prior to the start of my driving. By the time I was on my way the CEL had turned off and stayed off during a 2+ hour drive. Today temps were in the 30s when I first started the car and the CEL was on by the time I got into the car after remote starting. Stayed on the whole drive back home.
 

Mooseman

Moderator
Dec 4, 2011
25,257
Ottawa, ON
In cold, things shrink, like gaskets and seals. It's happened when it would leak when cold and seal up once it heats up and expands. A code would usually clear itself after a couple oif drives but if the condition returns, it will come back on.

I'd say try to find the leak when cold using carb cleaner.
 

TB_n00b

Original poster
Member
Dec 19, 2011
121
Queens, NY
Also...that's a bit of oil in an odd place to find oil, right? And the vacuum leak test didn't indicate any leaks. guess we'll see how it goes.
 

TB_n00b

Original poster
Member
Dec 19, 2011
121
Queens, NY
Le sigh...

Now that it's above 60 degrees we are back to constant CEL with misfires on cold starts.. Power was definitely suffering yesterday while trying to enter the highway as well. guess I am pulling the solenoid again to check the screens.
 

TB_n00b

Original poster
Member
Dec 19, 2011
121
Queens, NY
Le sigh...

Now that it's above 60 degrees we are back to constant CEL with misfires on cold starts.. Power was definitely suffering yesterday while trying to enter the highway as well. guess I am pulling the solenoid again to check the screens.

And I cleared this up by pulling and cleaning the CPAS again, doing another clean of the TB and doing a battery disconnect. Maybe this is just going to be a regular maintenance item I need to do when the weather changes each fall and spring.
 

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