I have a miss in cylinder #4. It's not that bad above about 2200rpm, but below that it is really lopey. The situation that lead to it was when I went to pass some guy, I was already in the other lane and beyond the point of not backing off when I saw traffic coming from the other direction so I had to mash the gas to get around the guy, as soon as I let off the gas I noticed the miss. So far I've replaced the spark plugs, plug wires, distributor cap and rotor, adjusted the timing, replaced the fuel filter, my #4 fuel injector (new injectors came from a junkyard and was replaced before and after the fuel filter), and have done a compression check. All of the items have helped but not solved the issue, and I'm starting to run out of ideas. So if any of you have anymore ideas all are greatly appreciated, thanks for reading.
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Last edited by bluecb7; 08-26-2010, 10:53 PM. -
did u check to see if u are getting the right amout of compression,aka compression check? -
Compression check.
you may have detonated (at the wrong part of the cycle) in cyl 4. you may have a head gasket leak at the cylinder because of it. (Or it may have given way even without a detonation) You may have a valve sealing issue because of it. Lots of possibilities.
Take a look at the spark plug when you pull it out. I forget what detonation damage looks like but someone here can tell you or you can find out on the web.
Another possibility is damage to the piston due to detonation.
In sum, do a compression test and a leakdown test and examine your spark plug on cyl 4.Last edited by batever; 08-26-2010, 03:10 PM.Comment
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Check if the EGR is leaking.
Had a car in yesterday with the same issue, changed the EGR and problem fixed.
Car Safety / General Servicing Checks --------Basic suspension checks
My 5.7 LS1 Holden Ute
A "Finished" project car is never finished until its been sold.
If at first you don't succeed, Try again. Don't give up too easily, persistance pays off in the end.Comment
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Did you check the condition of the spark plugs when you changed them? The spark plugs will tell you a lot about what is going on inside that cylinder.
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the first thing you should have done instead of throwing parts at it is a compression test ...Comment
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Sorry about that, part yes I have done a compression check, all cylinders are within 10% and 10 psi of each other.Comment
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How about the spark plug condition when you changed them?
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The plugs looked fine, just in need of replacement from normal wear.Comment
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Anyone else have any ideas?Comment
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Saying they look fine doesnt really tell us much, here is a good website to reference how plugs should look and what they look like when things go bad, unfortunately you would have to whitness these in person to do the sniffer test... and yes you can tell a lot by the smell too.
By fine do you mean it looked like this:
Or this:
The second one is after it burns out...Call me Travis.
2006 Cobalt LS/SC ~ "Burt the Bloody Bumble Bee"
1992 Accord LX ~ "Smoothie"
1991 CRX Si ~ Hellion
1989 GMC S15 ~ Oldie
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Car Safety / General Servicing Checks --------Basic suspension checks
My 5.7 LS1 Holden Ute
A "Finished" project car is never finished until its been sold.
If at first you don't succeed, Try again. Don't give up too easily, persistance pays off in the end.Comment
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intake leak?Comment
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