5.4, COP, code 0174 0175, 0304 and PCVs...

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Apr 2, 2005 | 09:47 PM

alexmunro

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5.4, COP, code 0174 0175, 0304 and PCVs...

Okay this sounds like the typical 5.4 miss that everyone experiences. I had the problem a few months ago and found this web site (pure GOLD). I followed the on line instructions to change spark plugs and pulled the number 4 COP (because it has been voted most likely to die). I swapped it for the number 5 COP because it would be easier to reach when I bought the new coil. Well it ran fine after that. Cleaning it up does wonders...

Now it runs like crap again, pulled multiple codes and here they are:

0171 system lean, bank 1
0174 system lean, bank 2
0304 engine misfire, cylinder 4 (the clown told me cylinder 5, so guess where the new COP is???). I'm headed back out to swap the 4 and 5 (the 5 was full of rusty water, so I'm glad I was in there anyway.

I have a long list of possible causes for the lean banks. Does anyone here have an idea of items most likely to fail?
Thanks in advance
-alex

Apr 3, 2005 | 11:08 AM

IB Tim

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Apr 3, 2005 | 11:16 PM

LxMan1

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From: Louisville,Ky.

The 2 most common ones are a dirty MAF or a cracked PCV hose. Usually the hose cracks back in the bend behind where it attatches to the intake.

Last edited by LxMan1; Apr 16, 2005 at 08:25 AM.

Apr 15, 2005 | 07:52 AM

KyF150SCowner

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5.4 miss

I had this problem, check out the thread on 5.4 intermittent missing if you haven't already. I have a 2001 SC with 71,000 miles. Have changed 2 COP's after finally getting a code P306 last fall, and a code P307 recently. Found that cleaning the plugs and the plug boots helped for a few days, then back to missing again. It would miss under load, from 1000 to 2000 RPM, while accellerating. Now I have changed all 8 plug boots. NAPA has a set of boots for $25.00. This cured the missing problem. I think that the boots break down after time, and allow the spark to jump to the head. Getting the plug and boot wet makes it happen sooner. The COP's don't actually fail that often, it's mainly moisture or a bad boot that causes the spark to jump to the frame. Kind of like the old bad plug wire problem. I put one of the original COPS back in with a new boot, and it is fine. Boots cost $3 to $4 each, much better than changing COPS for $60 to $80 each.

Anyway, my SC is running fine again...try the boots and Good luck!

Dec 8, 2005 | 12:15 AM

JMR

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From: DOG BOX

Sorry to hijack the thread but need help. Say that two different cylinders are misfiring to the point that the computer shuts off those two fuel injectors.....how do you get the computer to turn them back on once the problem is corrected.

thanks, john

Dec 8, 2005 | 07:36 AM

KyF150SCowner

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I would try disconnecting the battery, and leave it off for at least a few minutes. That should cause the computer to be cleared of codes. There may be a way to reset the codes from the diagnostic connector, but don't know how to do that. Good luck!