misfire/vibration at highway speeds
#1
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misfire/vibration at highway speeds
so many of you know my ongoing saga with my misfires on bank 2 (P0300,0305,0307,0308) that i get when cruising on the highway at 72-75mph. (i also have a rough idle) At that speed i get a strange vibration/shudder in the car that comes on at about 2000rpms and then is gone by 2200 or so...but recently i have noticed that i get misfire codes and a flashing CEL after that occurs or during it. Not EVERYTIME mind you just intermitently. Ive done POSs, plugs, i have a new CP on cyl 8 (yet still get a code). i also got a recent p1136 code (bank 1 lean). Any ideas as to how to fix this? ive looked at all my hoses, done the old school "spray carb cleaner on the hoses while the car is on" trick to check for vac leaks, even pulled one of the rear breather hoses. Anyone?
#2
AudiWorld Super User
are you getting any noise/rattle from the CATS? From my experience, they don't last forever
on these. If it's broken inside, you might not get a code either. Just a thought.
Bob
Bob
#3
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naw...no real cat noise...car is quiet it just freaks out at 72mph!...
the CEL will flash, stay on then the car will either ride normal or run really rough til you shut it off and then turn it back on...then its fine. any ideas?
#4
Have you vaged the O2 ??
Also remember no silicone spray anywhere near the air intake or you will destroy the o2 sensors.
Your problems seem to be related to fuel starvation.
ie: problems at higher speeds or after Spirited driving-Cylinder #8 missfire [remember #8 is the last on the rack so a shortage of fuel will most likely show up there] and lean codes.
I say again "evap valve" although you should also try to replace your fuel filter.
Your problems seem to be related to fuel starvation.
ie: problems at higher speeds or after Spirited driving-Cylinder #8 missfire [remember #8 is the last on the rack so a shortage of fuel will most likely show up there] and lean codes.
I say again "evap valve" although you should also try to replace your fuel filter.
#6
There is probably a proceedure here or Audipages somewhere-yes easy and cheap
Make sure the tech checks the operation of the evap valve as well.If you need any info on this email me.
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#9
Carrier bearing - OT
Recap - we have similar vibration issues.
While my car is in the shop for some other service, I'm going to have them check out my carrier bearing in order to eliminate another variable. If it is out of spec, I'll let you know and you may consider having yours looked at, too.
I get the odd vibration at 40-60 mph but don't recall if you also have wheel shake. My wheels are balanced, so it may be related to the other vibration. Or, it might be the rotors since I had them refinished some time ago and the vibration went away for a while. Perhaps the Akebono ceramic pads I am using leave too much gunk on the rotors? I don't know.
The idle issue isn't as bad as it once was. Once I fixed the breather hoses, the idle smoothed out just a bit. However, I get a substantial change in idle quality between P,N and the other drive gears. In P or N, the idle is smooth with a very slight shake. In R,D or 4, the idle drops quite a bit (expected) and the car shakes. And, I have no codes, which is different from your case.
While my car is in the shop for some other service, I'm going to have them check out my carrier bearing in order to eliminate another variable. If it is out of spec, I'll let you know and you may consider having yours looked at, too.
I get the odd vibration at 40-60 mph but don't recall if you also have wheel shake. My wheels are balanced, so it may be related to the other vibration. Or, it might be the rotors since I had them refinished some time ago and the vibration went away for a while. Perhaps the Akebono ceramic pads I am using leave too much gunk on the rotors? I don't know.
The idle issue isn't as bad as it once was. Once I fixed the breather hoses, the idle smoothed out just a bit. However, I get a substantial change in idle quality between P,N and the other drive gears. In P or N, the idle is smooth with a very slight shake. In R,D or 4, the idle drops quite a bit (expected) and the car shakes. And, I have no codes, which is different from your case.
#10
The fuel filter is restricted at 2000 rpm then unclogs above 2200 rpm? Unlikely.
Remember, the fuel pump runs at the same speed regardless of how much fuel the engine needs, the extra being returned to the tank by the fuel pressure regulator.
Tom
Tom