Missing and poor performance.

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mistermaclincoln

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I am working on this on behalf of a friend of mine who is tired of the stealership. She has less than 100,000 miles on her 2000 Nav and they are trying to sell her a new motor. Below is what the codes from the stealership found. Can anyone tell me how could the vehicle have a cylinder head issue?

Thank you

Checked for codes, P0304, P0032. Ran Oasis. Found TSB for misfires. Performed relative compression. Found cylinder 7 with low compression. Possible cylinder head issue. Cylinder 4 may need coil and spark plug. did not inspect yet due to access issue and base engine issue with cylinder 7.

I think the mechanic changed the coil and spark plug on cylinder 7 not
4.
 
If your loosing compression......I would say the first thing comes to mind is a bent valve.

It happens.

Do you have an independent mechanic that can run some compression test and run the codes?

Second opinion is always good.
 
Yes, I think that she will have the shop do the test but I am going to have you go to someone I can trust.
 
I had my 98 Expy 4.6 bend a valve and break the spark plug in half messing up the cylinder. It ran and drove but it missed. After I took the head off the cylinder was gone....I ended up getting a reman.

Good luck.
 
Now that is not the way to start the NEW YEAR!!! What can cause this to happen? I haven't talk to her yet but I think that this is what has happen. I want to see and maybe talk to the tech that is working on the car.
 
I think mine was due to a few things, mostly the previous owner doing headgaskets that failed and not being honest about all the work done,
 
I heard shortly after I bought my 05 in 2012 the #7 cylinder has a problem with overheating due to poor cooling in the head. I've also been told they fixed the issue in the newer replacements. This may be something you may want to look into.
 
No, I don't know yet until I get the paperwork. I know that there is a range for each cylinder but wouldn't a bent valve make some kind of noise? They have already changed 1 COP already and there might be another one. Which is causing a miss. They changed a bad vacuum line in May which was causing the motor to die on her. You would think that if the #7 COP was missing that the tech would have changed it also and not complain about it being in a bad spot. My question is what lead the stealership to check the compression on #7 anyway. That is the last think that I would have checked. They want her to buy a new motor since all they like to do anyway is replace parts anyway.
 
Elemino said:
I heard shortly after I bought my 05 in 2012 the #7 cylinder has a problem with overheating due to poor cooling in the head. I've also been told they fixed the issue in the newer replacements. This may be something you may want to look into.
Click to expand...

I will surely check this out. This sounds like a electrical or emission problem. The reason that it is missing could be TPS, Mass Air ect.
 
Elemino said:
I heard shortly after I bought my 05 in 2012 the #7 cylinder has a problem with overheating due to poor cooling in the head. I've also been told they fixed the issue in the newer replacements. This may be something you may want to look into.
Click to expand...

this is true. the 4.6 DOHC 4 valve had bad cooling in one head. cylinders 7 and 8 were affected. fixed around 04 i think? later 04 cobras and marauders are supposed to be better.

that corner of the engine would get loud and tick because the heads/cams/followers/etc would get hot and warp.

unless it ticking noticeably, that's probably not it.

mistermaclincoln said:
I will get the numbers!!
Click to expand...

do that.
icon14.gif
 
That was supposed to say when I bought the truck in 2010, not 2012.

@Chris I heard it also affected the 3V 5.4's (used from '03 to 06) in our trucks as well. I haven't researched it much though, because I don't really have any issues with my engine. The two problems I have come from plugs that need to be replaced and a wife that drove my truck an entire summer and thought she should try to break the steering wheel turning it after lock and nearly ruined my power steering pump.
 
hmm. can't say that i've read anything like that in the 3v 5.4s.
just in the dual cam 4.6s.

not impossible, i just haven't heard of it.
 
Well, here is the latest. I got a email letting me know that the 2000 NAV is not missing anymore. I said to myself hmmm. I ask her what kind of gas was she using and she said that she doesn't use premium anymore and she is getting her gas from Safeway. I guess that is better that ARCO but I think we have a person who is having either a low level gas situation and water and other crap that is running in her fuel tank. I told her to use Chervon premium for about a month and when that CEL light comes on again to bring it down to me and I will have the codes read for her at my buddies shop. Let me know your thoughts. More to come.

Thanks
 
mistermaclincoln said:
Well, here is the latest. I got a email letting me know that the 2000 NAV is not missing anymore. I said to myself hmmm. I ask her what kind of gas was she using and she said that she doesn't use premium anymore and she is getting her gas from Safeway. I guess that is better that ARCO but I think we have a person who is having either a low level gas situation and water and other crap that is running in her fuel tank. I told her to use Chervon premium for about a month and when that CEL light comes on again to bring it down to me and I will have the codes read for her at my buddies shop. Let me know your thoughts. More to come.

Thanks
Click to expand...
Face-palm... the idiots that sold me my truck went to put gas in it. They used regular, and the truck ran like crap until I burned through it. A friend of mine that's into racing said pour in some B12 when that happens. Not only does it clean the fuel system, but it acts as an octane boost. Tell her if she doesn't want to use premium, it may be time to consider a new vehicle. One that uses regular.
 
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