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99 beetle 2.0 automatic, started to run rough when cold when when warmed up it's ok, but now it's running very rough when cold, and not drivable when cold, car will not go, acts like it wants to stall but never does, once the blue coolant light goes out then it instantly starts running better, just a little miss, usually doesn't have any codes but once in a while it will show the random misfire code.

I replaced the MAF sensor, coolant temperature sensor, both oxygen sensors, coil, spark plug wires, spark plugs, fuel regulator, fuel pressure from pump is good, replaced catalytic converter. Even replaced the coil again just in case I got a bad one and then again just in case I got another bad one, also replaced the spark plug wires again and the spark plugs again just in case.

Don't know what it could be, I have a new throttle body but I don't want to waste time putting it in if that could not be the problem, also have a new EGR valve but I think the one in the car is ok. I don't think there are any vacuum leaks, I looked all over and it doesn't sound like there is.

When it's running very rough while I wait for it to warm up, if I press on the gas, it seems like it's a tiny bit of a back fire
 

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Have you scanned the car for trouble codes? What are the fuel trim levels and are the MAF readings, in spec? What brands of parts; did you replace everything with? Aftermarket sources; for crucial parts, like the MAF and 02 sensors, can cause allot of problems (Bosch oem parts; being the preferred correct parts). Checking the part #'s and the brands of all the parts, could be a good idea to ensure they are the correct parts and not adding to/causing the problems you are having. Do you have access; to a scan tool? Getting a scan tool; that can read live data could be helpful in troubleshooting your problem; check out the inexpensive ELM327 OBD II adapter on amazon and a app, that could run on your apple ios("wifi")/Android(Bluetooth) phone or tablet. Unfortunately, throwing parts at the problem and not being able to "see" what is going on; can end up not fixing the problem.

http://www.amazon.com/s/ref=nb_sb_noss_2?url=search-alias=automotive&field-keywords=elm+327

Fuel Trim Info - Ross-Tech Wiki

Sometimes, with the 2.0L; the throttle body will get really dirty and cause rough idle issues. Have you cleaned and aligned the throttle body?
 

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Off the top of my head, here are questions that I am asking myself ...

1) Did you replace the Coil Control Module?
2) Did you check the CAM and Crank Sensors?
3) Does the SAP still work?
4) Are you using Stock OEM Spark Plugs?

Also, if it were me, I would replace every vacuum hose anyway; it is inexpensive and might assist in identifying the problem.
 
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