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View Full Version : how to cure missfire finally.



ktm733
08-01-2013, 12:39 AM
This post is every culprit ive had with my 3.0 missifre. First things first get a scan tool, or vag com. vag com ks better because you can do basic settings and see actually what cylinder is missfiring and when. So first thigns first vacuum line are a huge missifre cause. Replace them with new vacuum hose which you can buy on ebay. Be gentle with the nipples they tend to break. Next thing is change your spark plugs, very cheap so do that firsr, while changing them check to see if oil is in the spark plug hole as a leaking valve cover gasket with let oil into the spark plug cause missfire. Next checking a coilpack is easy, but there is to types of bad coil packs i have found. One is when you floor your vehicle and it stutters then one of your coilpacks are going. Next the coil pack will straight up be dead and cause really bad missfire. To test coilpaock just simply have vehicle running and unplug coil pack. If the idle changes then the coil is good. Next fuel injectors, do the same thing while car is running and unplug one at a time see if idle changes. Next is the maf/ mass air flow sensor, this will cause missifire, test buy unplugging and if no change occurs then its bad. Next is the pcv system, check this by undoing the oil cap while vehicle is running. If a change occurs then its bad. The next thing is your fuel filter, yes this will cause missifre. Trust me it happened to me every single one of these if repaired to cure missifre. We are not done, the next thing is your battery being dead. Its said that a dead battery can cause a missifre. Almost forgot the big one, YOUR TIMING! check this by lining up the marks on the crank. You will have to manual crank engine to line marks up. Next is your intake manifold. There is an actuator or whatever they call it in the front with vacuum line hooked up to it. There are two bolts holding it. When you pull it out the rod thing should come with it. If not then its broke and need replacement, find one at a junk yard for about $100. Next is the o2 sensors, i didnt replace them but people state they can cause missifire. Also a plugged exhaust will cause missifre. Low fuel pressure can cause missifre. The next is wirring to the coil packs if brittle or broke will cause a missfire. I think thats about it on the missfire topic with the 3.0. Ive destroyed this missfire and no longer have it haha go ahead and and some, i might of forgot some. If you nesd pictures or help go ahead and ask, i documented everything. F you missfire i win!![wrench]

03a4b6ztk
08-01-2013, 07:30 AM
Question, are you sure on the PCV test? undoing the oil fill cap changing idle is indicator of bad PCV? Because mine seems to stumble if I take the oil cap off.

Reason I ask is because I believe my PCV is causing my low oil indicator to come on. Strange I know but I did a write up on the effects I see from this

imnuts
08-01-2013, 11:09 AM
If the intake adjustment arms are broken, it should not cause any misfires unless something breaks internally on the intake manifold. All the arms do is move runners to change the distance air travels in the intake manifold. If it isn't working, then you just lose torque or power, but it shouldn't be causing misfires. Also, if your car is misfiring at idle, you're going to know it without pulling coil pack plugs.

ktm733
08-01-2013, 11:11 AM
If you own a 3.0 early 02 engine then its because your engine isngoing. In thebearly 02 audis they were crap with the oil pump i think it is. The pcv might cause it but not for sure. But i think im right. I will look it up real quick.

ktm733
08-01-2013, 11:25 AM
If the intake adjustment arms are broken, it should not cause any misfires unless something breaks internally on the intake manifold. All the arms do is move runners to change the distance air travels in the intake manifold. If it isn't working, then you just lose torque or power, but it shouldn't be causing misfires. Also, if your car is misfiring at idle, you're going to know it without pulling coil pack plugs.

That what i ment by whwn thw intake manifold thing break. And will actually cause missfire some how. It cured my missfire at idle.

imnuts
08-01-2013, 03:05 PM
If you have a misfire at idle, something else is causing it. There are people that have had the arms break on both sides and no issues other than a loss of power. If you wanted, you could remove them entirely and lock the intake runners wherever you wanted them, but you'll effect the torque/power in some manner.

Also, the problem with the 02 model year, and very early 2003, was cams that were not hard enough. Subsequently, the cam lobes were wearing down excessively which would prevent valves from opening/closing when they should. It may have been an oil problem, but people experienced the issue even with proper oil/oil changes.

ktm733
08-01-2013, 10:41 PM
If you have a misfire at idle, something else is causing it. There are people that have had the arms break on both sides and no issues other than a loss of power. If you wanted, you could remove them entirely and lock the intake runners wherever you wanted them, but you'll effect the torque/power in some manner.

Also, the problem with the 02 model year, and very early 2003, was cams that were not hard enough. Subsequently, the cam lobes were wearing down excessively which would prevent valves from opening/closing when they should. It may have been an oil problem, but people experienced the issue even with proper oil/oil changes.

This guy has his facts haha. The rotating thing in there for some reason would only cause missifre when i floored it and then it seatled dow to idle and it would missifere. Not the arms breaking just the rotating this didnt even connect to the actuator. The reason for this post is to give people ideas about the missifre problems and what coukd cause it.