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I purchased an 01 1.8t b5 last November. The misfire codes are driving me crazy. I have installed new coil packs, a new maf, new fuel filter, new platinum plugs, had compression test, and smoke tested the vacuum lines. It still shows misfires on cylinders 1&3 as well as running lean. Compression is 125 on all cylinders. Last mechanic said fuel pressure is at 70 and should be 50. He said injectors were clogged. Also idles rough sporadically. I have run two tanks of chevron injector cleaner. I need help before I trade this in for a Volvo.
 

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Crazy question here, but where did you get the coil packs? I had the exact same issue with my 03 1.8t and I was using coil packs from the auto parts store. My mechanic said to use VW coil packs only. These motors are very finicky and the average coil pack won't do. Once he replaced them with VW parts, never had a problem since then. Just a thought. Good luck!
 

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I would check the coil pack connector/plug. They're made of plastic and exposed to the heat from the valve cover, overtime they get brittle and break inside.

I always share this because it was my personal experience with my daily driver. I bought it from the original owner, the car developed a misfire on cylinder # 2, only. I bought it like that and eventually I found out that the coil pack connectors were on their way out. I ordered the 4 of them at the dealership and the car has been trouble free for the past 3+ years.

Just my $0.02 :thumbup:

BTW, Passat > Volvo :D
 

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snug and tight according to the last mechanic
mine were like that, just coming apart from the inside. Previous owner took the car to 2 different VW dealerships and several mechanics. They replaced MAF sensor, coil packs, spark plugs, o2 sensors trying to fix the problem. After a few pretty expensive bills he let it go.
 

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2004 GLS 1.8T
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I purchased an 01 1.8t b5 last November. The misfire codes are driving me crazy. I have installed new coil packs, a new maf, new fuel filter, new platinum plugs, had compression test, and smoke tested the vacuum lines. It still shows misfires on cylinders 1&3 as well as running lean. Compression is 125 on all cylinders. Last mechanic said fuel pressure is at 70 and should be 50. He said injectors were clogged. Also idles rough sporadically. I have run two tanks of chevron injector cleaner. I need help before I trade this in for a Volvo.
Running lean will cause misfires. I was having light and intermittent misfires on my 2004, along with a P0171 lean code. Serviced the PCV system and both went away. Also, as others mentioned, it matters if you use original parts. For instance, you specify platinum plugs, but were they the correct platinum plugs? The 1.8T is fussy; anything other than the exact factory-specified plug can cause problems. Finally, if your tech is sure the injectors are clogged and not just guessing, bottles of cleaner may not do it; you can send the injectors out to be serviced. It's about 1/3 to 1/2 the price of new ones.
 

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Finally, if your tech is sure the injectors are clogged and not just guessing, bottles of cleaner may not do it; you can send the injectors out to be serviced. It's about 1/3 to 1/2 the price of new ones.
That's what I'd suggest also. Misfiring and "running lean" goes hand-in-hand; misfires dump unburned Oxygen at the O2 sensor, and that can be due to ignition or injector problems. You can also swap injectors 1 & 3 with 2 & 4. If that's where the misfires go, then you know the problem is injectors.
 

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Discussion Starter #9
Factory specified plugs were used. Last mechanic said fuel pressure was 20 pounds over normal and there was no gas on the plugs at all. Hew said considering everything else that had been replaced the only other thing he could think of were the injectors. When the fuel filter was replaced mechanic said it was first time it had ever been replaced. The original was still on the car and loaded with black gunk. The car has 147k miles. Fuel filter was replaced 2k miles ago.
 

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Amazingly, VW considers the fuel filter a lifetime part that doesn't need replacing. Still not a bad idea to do it every 50,000 miles or so. (Though I admit my 2000 ran fine with a 200,000 mile fuel filter in it).
 
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