G35 Sedan V35 2003-06 Discussion about the 1st Generation V35 G35 Sedan

Rough Idle on my '05 G35

  #16  
Old 11-10-2014, 10:02 PM
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Have you done an idle relearn?
 
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Old 11-10-2014, 10:24 PM
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Originally Posted by markc View Post
Have you done an idle relearn?
No I have not. should I do that now?
 
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Old 11-11-2014, 05:26 PM
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update: car still will not run for more than a short while but I finally got it to throw a code.

Cylinder 2 misfire P0302

now remember I swapped #4 and #2 around (fuel injectors) and #4 was the one previously misfiring. So I believe I have found the problem. I have ordered 1 fuel injector and will replace the faulty one. I have also ordered some new gaskets for the plenum assembly in case there is a leak from us taking it apart (causing it to not run). There were no other codes besides the misfire so I am going to assume it is a combination of leak from the poor old and disturbed plenum gaskets (200K miles is a lot lol, after disturbing these gaskets they might not be sealing right) and the bad injector. So theoretically once we get the parts in and replace it, the engine should at least run!

A week or two later we will replace the rest of the injectors, the spark plugs, and find a coupler for the intake (cant find one anywhere, might stop by the junkyard lol) and we should have an engine good for at least another 50-100K miles (at least I hope so lol its been driven hard but it is well cared for [oil,air filter, and such])

will let you guys know the results of the new injector and gaskets. Which leads me to one more question... what is the best way to clean the plenum itself (its kind of dirty, especially around the TB area, lots o black) ? and what is the best way to clean the old gasket pieces that will be stuck to it?
 
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Old 11-11-2014, 09:14 PM
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Very stiff plastic putty knife for gasket removal, (it is aluminum and can be easily gouged with metal), and carb cleaner for the plenum.
Hopefully you have found your problem and can carry on beating on that VQ.
 
  #20  
Old 11-16-2014, 06:02 PM
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G35 sedan w/ too much money in mods
Originally Posted by Mustang5L5 View Post

Basically it's Fuel, spark air and compression. You've checked spark without luck, and i assume the air intake is free from squirrels and other obstructions, so since it's easier, i'd check compression on all 8 cylinders before investigating a fuel issue (with me suspecting a failing injector)
I forgot you had the rare 8 cylinder G.
 
  #21  
Old 11-17-2014, 09:46 AM
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Originally Posted by Blue Dream View Post
I forgot you had the rare 8 cylinder G.
I wish.


I post here and on a few Mustang forums. SOmetimes I forget where I am.
 
  #22  
Old 11-17-2014, 09:51 AM
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Originally Posted by Scredeur4 View Post
will let you guys know the results of the new injector and gaskets. Which leads me to one more question... what is the best way to clean the plenum itself (its kind of dirty, especially around the TB area, lots o black) ? and what is the best way to clean the old gasket pieces that will be stuck to it?

Glad you think you found the cause.


You can probably use a combination of degreaser plus carb/brake cleaner to clean the manifold. I assume you have that black/orange oily residue coating it? In that case a strong enginer degreaser plus carb cleaner might do the trick.
 
  #23  
Old 11-26-2014, 04:08 PM
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Ok guys here is an update, the car still isn't running very well.

we replaced all the spark plugs, all the coils, injector #2 (you see, we swapped injector 2 and 4 around to see if #2 would misfire, it did so we bought an injector), the PCV valve and its hose was replaced. Also changed the intake coupler by buying a new intake off of eBay.

spark plugs #5 and #6 both had oil on them., noticed some oil on the bottom of the valve covers.


when we had swapped the injectors around, the car wouldn't idle anymore. then when we got the new injector in to replace the faulty one, the car then said the misfire was random or multiple. (p0300)

The car is still randomly/multiple misfiring. changing all the spark plugs and the coils and the intake lets it idle now, but still misfires, shakes (a lot), etc. revving it up to 4000rpm or so and its smooth. so it just cannot idle properly without misfiring.


We ordered the rest of the injectors. Thinking about replacing the valve covers since they are leaking oil into cylinders 5 and 6, and even a little bit is leaking out of them.

if you guys have any other ideas let me know. oh and the plenum gaskets were changed. just running out of ideas over here on how to fix it
 
  #24  
Old 11-26-2014, 04:40 PM
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I would replace the valve covers, I believe that is what Nissan did while this happened when the vehicle was still under warranty.

*EDIT - I previously wrote some advice when I judged the thread by it's title and did not read the entire thread, sorry.
 

Last edited by cmaster; 11-26-2014 at 04:45 PM.
  #25  
Old 11-26-2014, 05:37 PM
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Originally Posted by cmaster View Post
I would replace the valve covers, I believe that is what Nissan did while this happened when the vehicle was still under warranty.

*EDIT - I previously wrote some advice when I judged the thread by it's title and did not read the entire thread, sorry.
do u think the valve covers can cause a misfire or are a part of the problem? I mean I know they need to be changed anyway but im just curious.
 
  #26  
Old 11-27-2014, 02:33 PM
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Please note, I've had my G for three years now and haven't had to do anything other than the standard maintenance on it. My wife's Jeep XJ with 250K+ miles on it has given me some headaches, even though that 4.0L I6 is pretty bullet proof. This is what I would gather with my experience on that thing:

No the valve covers should not affect your idle. Whenever I hear a rough idling complaint though I typically start looking at vacuum hoses, start the car up and look for broken hoses by taking a squirt bottle and squirting bits of water, if you see any bubbling you likely want to replace that hose, which may or may not be the sole reason for a rough idle.

My second guess, when providing a keyboard diagnosis, is to look at throttle body. Is it dirty? Give it a good cleaning. I usually use some dish soap and a tooth brush. Again, this may only be a part of the problem.

My third guess, while rough idling, disconnect the throttle position sensor. If the car starts idling like normal, that's your problem.

The crank position sensor I've seen throw some crazy misfires as well. The trouble with this on most cars is that it doesn't quite throw a code at the ECU until it completely fails and stalls the car. By the time you can get it to a scanner if you don't have one the check engine light turns off. Why? The CPS tends to fail when it overheats (that's why a lot times it only happens when the car has been running for sometime or during the summer time) but when it cools back down, it goes back to somewhat normal operation and the vehicles runs fine.

Hope this helps.
 
  #27  
Old 12-01-2014, 08:54 AM
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Originally Posted by Scredeur4 View Post
do u think the valve covers can cause a misfire or are a part of the problem? I mean I know they need to be changed anyway but im just curious.
Only if the leak is severe enough that the oil is pooling up into the spark plug boots and intereferring with the COP and plug connection
 
  #28  
Old 12-01-2014, 12:33 PM
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For the oil leaking in to the spark plugs it was the seal between the tube and the valve cover that was the problem with the Rev up but for your misfire we had a m3 come in to our shop with a similar problem well the exact problem except for being completely different cars. But it turned out to the vanos system was malfunctioning (BMWs version of vvtc) so that could be a possibility.
 
  #29  
Old 12-02-2014, 09:15 AM
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For a cheaper alternative to G35 valve covers, look into maxima covers. There is a write up on here.

They are half the price.
 
  #30  
Old 12-02-2014, 08:02 PM
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I have a passenger bank cover and gaskets if that's what u need.
 

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