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p0300, rough idle, codes come and gone?

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Old 11-09-2010, 01:43 PM
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Default p0300, rough idle, codes come and gone?

Hi guys,

Couple of questions. 2001 S10 Blazer, 4.3L, 4wD

1) I have a p0300 that always starts as a p0301. In other words, I clear codes, drive for 100 miles, and bam p0301. Then another 100 and the p0301 is gone and there's a p0300.

Thoughts: Random misfire. I've checked the spark plugs and wires (new). The plugs were gapped wrong, but those have now been fixed. The engine has 50k miles and is from a scrapped Blazer (2000).

2) (Related, I think). Had a friend hook up to my computer, and I have a huge problem with cyl 2 misfires. Like 40/100 cycles. But this doesn't start right at start-up. It goes like 500 cycles or so and then they start ringing up. Also, if I gun it, the misfires stop.

Thoughts: Injector(s)?

3) Really, really rough idle. When I come to a stop (and hold the brake), mild vibration. When I let off the brake (but don't give it gas), the car has a really rough shake (shake moreso than a vibration. It's rough).

Thoughts: ???? No idea really. Related to the misifres?

4) Had a p0410 and whatever the code is for the coolant thermostat. These both reset though.

Thoughts: Fluke? Seems weird to have 2 codes just come and go like that within the last couple weeks. But it happened.

5) EBCM, C0265.

Thoughts: I know I can send it in to any of a number of places. Is there a guide for removing/replacing one of these somewhere? I thought I read something about having to bleed the brake lines if I removed this; is that so?

Thanks in advance as always, guys.

-bkw
 
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Old 11-09-2010, 05:04 PM
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the miss fire sounds like it could be cap and rotor botton problem. very comon on the 4.3. Just replaced the cap and rotor
 
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Old 11-10-2010, 07:36 AM
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Cap and rotor new as of March. Put them on the new engine when we swapped it out.
 
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Old 11-11-2010, 10:42 AM
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And fwiw, the March tune-up was done with all AC Delco parts.

I know things fail, but the cap and rotor worked fine on my old engine (before it kicked the bucket), so I am not sure why the engine swap would cause them to fail.

Any other thoughts on this or any of the other questions/observations?

Much thanks.

-bkw

If I'm swapping out any injectors anyway, I'm considering upgrading to an MFI spider. Is this a reasonable effort to fix the misfires?

I don't mind putting the $ into the car; I'd just hate to spend $ needlessly and get nowhere.
 
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Old 12-01-2010, 03:20 PM
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Ok, maybe an easier question. I'm planning to swap the CSFI for an MFI Spider.

GM Parts Direct
12568332 MFI Assembly
88894355 Bracket
17113215 Seal Kit

$321.26 after shipping

or

AC Delco 217-3028
$442.89 @ Advance Auto Parts
 
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Old 12-01-2010, 03:37 PM
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Man... I know I responded to you earlier this month, but it's not here...

You can find the AC Delco part cheaper elsewhere. Amazon.com has it for $263.57.
 
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Old 12-01-2010, 03:47 PM
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Originally Posted by swartlkk
Man... I know I responded to you earlier this month, but it's not here...

You can find the AC Delco part cheaper elsewhere. Amazon.com has it for $263.57.
This makes me because I was looking forward to your response (and was trying to bump it often enough that you'd see it but not too often as to be annoying! :-p)

Thanks for the hint about amazon. Looking fwd to your response if you do get around to it, but I'm pretty sure all but the C0265 is going to be fixed (fingers crossed, anyway) by the new spider.
 
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Old 12-01-2010, 04:24 PM
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C0265/C0266 - EBCM Motor Relay Circuit

Search up on either of those codes as well. From what I recall from the past, this could mean that your ABS unit is bad.
 
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Old 12-01-2010, 11:50 PM
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Thanks, Kyle. I know the 0265 is my EBCM. Any advice? From OP:

Originally Posted by bkw
5) EBCM, C0265.

Thoughts: I know I can send it in to any of a number of places. Is there a guide for removing/replacing one of these somewhere? I thought I read something about having to bleed the brake lines if I removed this; is that so?

Thanks in advance as always, guys.

-bkw
 
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Old 12-02-2010, 07:05 AM
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I posted that so you could do some diagnostics if possible.

As far as removal, like I said, there are threads that should be able to be found using "C0265" as a search term that should provide further detail.

To name a few:
modulemaster.com ????
8 ABS codes

The EBCM can be removed without opening up the brake lines. It attaches to the valve body and can be removed fairly easily. The vehicle can be driven while the EBCM is removed however the ABS light will be on.

Check out the instructions on ModuleMaster.com.
 

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