Just found a blurb about the vacuum line to the fuel pressure regulator. That may cause the lean running condition. I'll check it tonight. I'll be changing all vacuum lines this weekend with 3.5mm silicone lines.

 

mass air flow sensor. Mine was doing the same thing with the same codes.

 

The funny thing is I bought my car not running. Put a head and also a turbo on it. I would start it up when cold, would run great for like 1 sec then would start missing and shit, then once it warmed up was smooth. I trouble shoot it a little, always had a feeling it was the MAF but didn't want to just throw one at it. I drove it over to the local VW dealer and it took 15 min and 90 dollars later it was the MAF. I replaced it and cleared the codes myself and the car has been great since.

 

Oh, just an FYI, the 2000 does not have an ICM. It's built into each coil. First thing is do the vac lines like you said.

 

Thanks tschacht and VAGguy. I only had time to replace a couple lines before the kids needed help with something. So I'll get to the rest this weekend. I got a misfire code on three different coils over the weekend. I doubt I have three intermittently bad coils so I'll check into the MAF. It does make sense that it runs like crap until that air pump shuts off if the MAF is having problems. Is there a way to clean it?

I'm wondering how a bad MAF could cause misfiring though?

 

incorrect airflow readings and inforrect fuel mixture will cause a misfire. gimme a minute and I will find the write up for the MAF.

http://www.passatworld.com/forums/showthread.php?t=256928&highlight=alcohol

http://www.passatworld.com/forums/showthread.php?t=124928

 

I cleaned my MAF using the directions in the first link. Now it actually runs worse than it did. Is there a way to check it with a meter? Also, after I bought the car, I took the whole intake system apart and oil just poured out from the intercooler (bad turbo bearings). What's the sensor that is plugged in just past the intercooler? Is it an air temp sensor? Could it be coated in oil and non functional?

 

Last time I pulled off my MAF to clean it, I noticed that the tiny little sensor inside (about the size of a finger-nail) was loose and barely hanging on. It subsequently broke and caused all the said problems you are having. Also, you want to make sure the MAF is installed in the proper flow direction. That will cause problems too!

 

Thanks one.eighty. I checked it again and it appears pretty solid.

I was at another VW site and someone recommended unplugging the MAF completely. If the cold idle problem went away, then the MAF was suspect. I tried this (unplugging the electrical connection to the MAF) and the cold idle became perfect and the car runs like a bat out of hell. Unfortunately, it stalls when you push in the clutch and come to a stop. So, I'm about ready to take the plunge and get a new MAF. I wanted any last words of advice before I do this.

 

Just a quick follow up... I replaced the MAF sensor and now it starts and idles perfectly, and has good smooth acceleration. Most importantly, NO CEL!!! Thanks to all for the advice on this problem.

 

I guess the MAF just went south. Congrats.