#3 missfire
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New User
Joined: Mar 2007
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#3 missfire
I have a 5.4L 4wd EB Expo with 165k on it. It is miss-firing on cylinder 3 according to the code reader. I have changed the coil, plug and injector on #3 with no effect. Any ideas what to check next, or how I check the components individually? EXample, how would I check the feed to the fuel injector or coil?
New User
Joined: Dec 2005
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From: kansas
If fuel flow to the rail was a problem you would have problems on the other cylinders as well on that bank. Since you changed the COP and plug and it didn't fix the issue the most logical thing to do would be a leak down check. If you can't do a leak down do a compression test and compare with the other cylinders to see if #3 is unusual in some way.
You can try to measure the +12v source to the coil when the key is on to see if you have a strang voltage drop but unlikely.
John
You can try to measure the +12v source to the coil when the key is on to see if you have a strang voltage drop but unlikely.
John
Elder User
Joined: Oct 2009
Posts: 619
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Keep us posted. I have an '00 EB 5.4 and just last night felt the hesitation, shuddering while driving between 45 and 55 mph. I thought my transmission was toast. I had just bought this 1k miles ago and mine has 175k on it. A little over an hour later the Check Engine Light came on and I was just going by an Advance Auto. Pulled in and they ran the code and said misfire on Cylinder #3. Funny thing is 1800 miles ago previous owner replaced all 8 plugs and had a misfire on #6 and they replaced the coil pack. I hope this is all mine turns out to be. Burnt valves seems a whole lot more costly. Good luck. Seems like these are commone issues with these engines. I asked my mechanic if I should just replace all 8 coil packs and he said really not worth the expense. Is he right or should I just have him do it for good measure.
I found these on ebay. Seems like it will cost this much to replace 2 from local auto parts stores and here I can get all 8. Anyone order from this company on ebay.
http://cgi.ebay.com/ebaymotors/Ignit...Q5fAccessories
I found these on ebay. Seems like it will cost this much to replace 2 from local auto parts stores and here I can get all 8. Anyone order from this company on ebay.
http://cgi.ebay.com/ebaymotors/Ignit...Q5fAccessories
Fleet Owner
Joined: Apr 2008
Posts: 24,322
Likes: 5,132
From: 0,0,1
Many of us around here installed the eBay coils and they work just as good as the OEM ones. The rubber boots on the bottom of the coil packs tend to dry out and crack. This condition allows spark to jump the side wall and ground out. So your coil could be good and just needs a new rubber boot. The boots go for $2-$3 each.
Elder User
Joined: Oct 2009
Posts: 619
Likes: 1
Many of us around here installed the eBay coils and they work just as good as the OEM ones. The rubber boots on the bottom of the coil packs tend to dry out and crack. This condition allows spark to jump the side wall and ground out. So your coil could be good and just needs a new rubber boot. The boots go for $2-$3 each.
Fleet Owner
Joined: Apr 2008
Posts: 24,322
Likes: 5,132
From: 0,0,1
Do you think I should have him replace all the rubber boots, all the coil packs or neither and just wait and see if others go bad? Since the plugs were replaced 1800 miles ago and now with misfire on #3 is it a given the plug is bad or do we just have to pull it and confirm?
