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misfiring but no codes

  #1  
Old 02-09-2013, 11:52 PM
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Default misfiring but no codes

Just hoping someone can help out...

I have a 2004 3.0 AVK. rebuilt the entire engine due to sludge about 2 years or 50,000 km ago (brand new heads and re-man'd bottom complete with complete t belt job and new slave cylinder but left in the original clutch) car currently has about 325,000 km on it.

so a few weeks ago I started up the car and it started to misfire, didn't throw any codes but after a few seconds it normalized. didn't notice anything at that point and it drove normally. a few days after i started it up again and the misfire came back. it did throw codes at this point and i took it to the mechanics. If my memory serves me correctly, it threw misfire on cylinders 2,4,5 and 6. And a random misfire code. The fuel pump had been making some noise for a while and since 2, 4, and 6 are on bank 2, furthest from the pump, we figured it may be a fuel issue and replaced the fuel pump and fuel filter.

Same problem persisted... its no longer throwing any codes

we checked vaccuum, mechanic said it was all normal, plus could not "hear" any leaks. he pulled all the coils and plugs and all looked to be well. our next step is to replace all 6 plugs, and buy an extra coil move it around to see if its a bad coil.

now on top of this, today i'm having a problem with the transmission. it's extremely hard to get it into gear once the car is moving. it seems that i almost have to drop the RPM for it to go into gear, and its somewhat intermittent. Sometimes it'll just drop right in, most of the time i had to let off the gas and shove it into gear.

I'm not quite sure these two problems are related but any advice at this point would be helpful, i'm tired of throwing money away.

i've been reading up on the net about these two symptoms and it points to a possible issue with the camshaft sensor. before my issue with the transmission my mechanic did suggest it may be a bad tensioner/belt, timing is off, or camshaft sensor, but he said to start with the plugs and coil to rule it out (and cheaper). just wondering if anyone can give some advice.
 
  #2  
Old 02-10-2013, 09:16 AM
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Originally Posted by markaudi
Just hoping someone can help out...

I have a 2004 3.0 AVK. rebuilt the entire engine due to sludge about 2 years or 50,000 km ago (brand new heads and re-man'd bottom complete with complete t belt job and new slave cylinder but left in the original clutch) car currently has about 325,000 km on it.

so a few weeks ago I started up the car and it started to misfire, didn't throw any codes but after a few seconds it normalized. didn't notice anything at that point and it drove normally. a few days after i started it up again and the misfire came back. it did throw codes at this point and i took it to the mechanics. If my memory serves me correctly, it threw misfire on cylinders 2,4,5 and 6. And a random misfire code. The fuel pump had been making some noise for a while and since 2, 4, and 6 are on bank 2, furthest from the pump, we figured it may be a fuel issue and replaced the fuel pump and fuel filter.

Same problem persisted... its no longer throwing any codes

we checked vaccuum, mechanic said it was all normal, plus could not "hear" any leaks. he pulled all the coils and plugs and all looked to be well. our next step is to replace all 6 plugs, and buy an extra coil move it around to see if its a bad coil.

now on top of this, today i'm having a problem with the transmission. it's extremely hard to get it into gear once the car is moving. it seems that i almost have to drop the RPM for it to go into gear, and its somewhat intermittent. Sometimes it'll just drop right in, most of the time i had to let off the gas and shove it into gear.

I'm not quite sure these two problems are related but any advice at this point would be helpful, i'm tired of throwing money away.

i've been reading up on the net about these two symptoms and it points to a possible issue with the camshaft sensor. before my issue with the transmission my mechanic did suggest it may be a bad tensioner/belt, timing is off, or camshaft sensor, but he said to start with the plugs and coil to rule it out (and cheaper). just wondering if anyone can give some advice.
i have same problem with transmission and an intermittent misfire that i cannot figure out as well. mine does not throw codes. it will misfire during a downshift and acceleration is when i feel the blimp of the misfire.. I've changed plugs multiple times, seafoamed the engine, replaced fuel injectors, and cleaned maf but problem still exists as well.

since you get codes for your misfire, try swapping the coil packs of the cylinders that show up to cylinder 1 and see if a misfire follows the coil pack.
 
  #3  
Old 02-10-2013, 10:14 AM
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Originally Posted by tofast2belast
i have same problem with transmission and an intermittent misfire that i cannot figure out as well. mine does not throw codes. it will misfire during a downshift and acceleration is when i feel the blimp of the misfire.. I've changed plugs multiple times, seafoamed the engine, replaced fuel injectors, and cleaned maf but problem still exists as well.

since you get codes for your misfire, try swapping the coil packs of the cylinders that show up to cylinder 1 and see if a misfire follows the coil pack.
Thanks tofast2belast. That's the plan, i only got those codes once. I've been driving it around for a couple of days and no codes yet...
 
  #4  
Old 02-10-2013, 01:30 PM
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anyone else have any opinions?
 
  #5  
Old 02-13-2013, 06:27 PM
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alot of times a small vac leak might cause this. The car will surge when it looses boost.
 
  #6  
Old 02-14-2013, 09:29 PM
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Originally Posted by pa4ul
alot of times a small vac leak might cause this. The car will surge when it looses boost.
thanks for the post, but not sure that it applies to this, its a 3.0...
 
  #7  
Old 02-15-2013, 01:30 AM
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Check the spark plugs and their gaps. The 3.0 should use NGK (5874) PFR6U-11G

As far as the transmission issue, given the mileage, I'd do a transmission fluid and filter replacement:
Audi 01V Tiptronic Transmission Fluid Change | Audiction
 
  #8  
Old 02-15-2013, 12:08 PM
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Originally Posted by markaudi
thanks for the post, but not sure that it applies to this, its a 3.0...
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  #9  
Old 02-16-2013, 09:50 AM
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thanks for the input guys, i'm gonna try them out!
 
  #10  
Old 02-18-2013, 12:42 PM
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yea. . .
 
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