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Seeking some assistance here. My 1999 2.0L AEG New Beetle (~189,000 miles) has been giving me crap. She likes to misfire and have oil fouled plugs. Over a year ago, she had both intake gaskets and then a few months later started having intermittent misfires on various cylinders. Being green and broke, I replaced the plugs and that seemed to fix things for a while. Most recently when it started happening again and the plugs were oil-fouled, we replaced the valve cover gasket, the plugs and the wires in addition to cleaning out the wells to remove any oil that was present. That was just a few weeks ago. However now, she's misfiring on cylinders 1,3 & 4. I'm attaching a photo to show what the plugs look like that were pulled this morning. The deposits on plug three are hard, bridged from one electrode to the center and covering all three electrodes. It can't be removed by scraping or hand use of a wire brush.

I have a new crankcase breather vent that we are installing but I don't really think that this is the problem since I see no evidence of cracks or failures in it. In the past year we have also replaced the crankshaft position sensor, engine coolant temperature sensor. Does anyone have any other suggestions for what could be causing the plug issues?
 

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Seeking some assistance here. My 1999 2.0L AEG New Beetle (~189,000 miles) has been giving me crap. She likes to misfire and have oil fouled plugs. Over a year ago, she had both intake gaskets and then a few months later started having intermittent misfires on various cylinders. Being green and broke, I replaced the plugs and that seemed to fix things for a while. Most recently when it started happening again and the plugs were oil-fouled, we replaced the valve cover gasket, the plugs and the wires in addition to cleaning out the wells to remove any oil that was present. That was just a few weeks ago. However now, she's misfiring on cylinders 1,3 & 4. I'm attaching a photo to show what the plugs look like that were pulled this morning. The deposits on plug three are hard, bridged from one electrode to the center and covering all three electrodes. It can't be removed by scraping or hand use of a wire brush.

I have a new crankcase breather vent that we are installing but I don't really think that this is the problem since I see no evidence of cracks or failures in it. In the past year we have also replaced the crankshaft position sensor, engine coolant temperature sensor. Does anyone have any other suggestions for what could be causing the plug issues?
How much oil are you going through? Volkswagen had some piston ring issues for a couple years. You should do a compression and leak down test.


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We're adding roughly a quart every 1000 miles or so. We'll probably get her down to to the father in law's place and do the compression test shortly.
 

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Get a scan tool that can read real time engine time and verify that the engine is running 205F.

Also make sure you do not have any vacuum leaks.

Lean conditions can cause misfires and poor crankcase vacuum can cause leakage past valve guides and piston rings.

The engine does have a lot of miles, so it is hard to know for sure the cylinder and ring condition.
 

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You will prob think I am mad but here goes

I used to have the same issue with NGK plugs , changed to Bosch and all has been good , I have the same oil usage but only 101k miles.
 

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fouled plugs

The plug well hole get's oil in it and eventually and slowely seeps down into the plug, well atleast on mine it did. common problem on these beetles so if you plan on keeping this car I would replace it anyhow. I'm surprised it went 189k miles until the gasket leak, mine started leaking at around 100k miles.
 

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Discussion Starter #11
Yes, we already replaced the valve cover gasket, as I said in the original post. Did the compression test dry and after 3 squirts of oil per cylinder. Results were:

Dry
1: 150
2: 145
3: 155
4: 150

Wet
1: 180
2: 200
3: 180
4: 175

Those are all normal and here's no variance more than 13.5% between any of the cylinders. So don't really know what's up with that.
 

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Discussion Starter #13
I'd actually read your thread before posting mine and before changing the breather vent. There is no sign of any yellow goo or other build up. Thanks, though.
 

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Find out how many Emission Reasiness monitors not clear your state will allow. Reset the CEL, then drive the car but not on highway for long, likely you can get Readiness Monitors to clear but not trigger the CEL then get car inspected.
 

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Find out how many Emission Reasiness monitors not clear your state will allow. Reset the CEL, then drive the car but not on highway for long, likely you can get Readiness Monitors to clear but not trigger the CEL then get car inspected.
I'm sorry, did I ask what to do to pass inspection or if anyone had ideas about what might actually be wrong with the car? I'm just a dumb female, after all. So perhaps I just don't know how to phrase things and am confusing you guys. If there's some way that I can be more clear, please let me know!
 

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Have you inspected the coil pack? They are known to crack and cause intermittent missing. Try misting it with water from a spray bottle while the engine is running and see if it causes a miss.

Also, I think my '99 AEG runs better on Autolite Double Platinum plugs than the NGK's.
 
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