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need help diagnosing my terrible misfire!

Old Oct 8, 2011 | 02:54 AM
  #1  
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Default need help diagnosing my terrible misfire!

It started last week, I put SHITGO premium gas from the hood bc the price was cheap. I ran a whole new tank of 93 from Shell along w/HEET and seafoam and it still misfired.

Today I changed the plugs w/NGK Iridium and the o2's back to new stock Delphi ones bc I was having o2 DTC codes like crazy . It ran GREAT and then started misfiring 15 minutes later on my way to work. They bank 1 plugs (TR5's) looked good but bank 2 was caked in soot, same for the o2's. What could it be?

A friend said he had similar problems when his fuel pump was on the out, but wouldn't it cause misfires on all cylinders not just 1 bank?

these were my common codes:

P0155
P0300
P0442
P0135
P0174
P0151

The drive home was terrible!! A co-worker followed me some what, and I could see the smoke pouring out. I went through a 1/4 tank and was popping like crazy. But it was intermittent, it would misfire then stop and then start misfiring again.... oh and no other codes besides the P0300 - multiple misfire one came on

Thanks
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Old Oct 8, 2011 | 10:49 AM
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Default need help diagnosing my terrible misfire!

It started last week, I put SHITGO premium gas from the hood bc the price was cheap. I ran a whole new tank of 93 from Shell along w/HEET and seafoam and it still misfired.

Today I changed the plugs w/NGK Iridium and the o2's back to new stock Delphi ones bc I was having o2 DTC codes like crazy . It ran GREAT and then started misfiring 15 minutes later on my way to work. They bank 1 plugs (TR5's) looked good but bank 2 was caked in soot, same for the o2's. What could it be?

A friend said he had similar problems when his fuel pump was on the out, but wouldn't it cause misfires on all cylinders not just 1 bank?

these were my common codes:

P0155
P0300
P0442
P0135
P0174
P0151

The drive home was terrible!! A co-worker followed me some what, and I could see the smoke pouring out. I went through a 1/4 tank and was popping like crazy. But it was intermittent, it would misfire then stop and then start misfiring again.... oh and no other codes besides the P0300 - multiple misfire one came on

Thanks
Reply
Old Oct 8, 2011 | 12:24 PM
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That is what my 02 did when the fuel pump went out, but the one bank thing is kinda fishy.
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Old Oct 8, 2011 | 12:53 PM
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Def need to check fuel pressure. do you still have cats?? the tr5s are quite a bit colder so def not hot enough to self clean. Backfiring or running bad at all would probably foul them pretty quickly. so I doubt they are your problem just an after effect
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Old Oct 8, 2011 | 02:14 PM
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exactly, I could understand if it was but the one bank think is losing me too
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Old Oct 8, 2011 | 02:16 PM
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I'll try to check the FP tomorrow. No the cats have been eliminated
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Old Oct 8, 2011 | 02:42 PM
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A lot of codes there friend. Seems like they are all emission/O2 related. What's up with the tune - do you have tuning software? That could help you a lot. It would be great if you could force it into open loop - or just to see if MAF, MAP, etc are operating correctly.

TR5s are stock heat range, ignore that.

Fuel pressure is a good idea.
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Old Oct 8, 2011 | 03:48 PM
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With your new software, run a log. Any exhaust leaks?
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Old Oct 9, 2011 | 03:08 AM
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after reading one of my logs on HPT, my bank 2 o2 isn't running.... I'm gonna try a crank relearn tomorrow and hope it helps.

Any other suggestions on what caused it or how to fix it?
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Old Oct 9, 2011 | 03:36 AM
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Sorry CASE relearn*

These are brand new o2's if you missed it up top!
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