Running problem after warming up.

Check coolant temp sensor. These fail often and cause all kinds of mystery problems. This unit acts much like a choke on old carb engines and can fail in different ways. Most common (I think) they fail such that the ECU thinks the engine is cold when it has begun to warm and thus the ECU delivers too long a pulse to the injectors so that the engine runs way too rich. I think it is also possible for the sensor to fail at any point between cold and warm such that the fuel mix is wrong except for the particular temp at which the sensor is stuck. Also O2 sensor has some fuel "trim" input.

Did you clean the idle air control motor, when you cleaned the throttle. Also check for vacuum leaks. The PCM controls the IAC motor. If it to dirty it can stick. Can cause a surge and stall.

insufficient battery power to stay running. replace battery or alternator.

the idle control motor probly worn-on the throttlbody--also the tps sensor - get intake area inspectd--a haynes manual will xplain complete car-partstore hazit--------starter fluid is used for low compression or weak spark

gas or diesel..

Your only problem friend, is the temperature sending unit/sensor. Upon cold start, this sensor wil tell the computer to go into cold start mode putting a bit more fuel in and raising the idle a bit to keep it running when cold without using the throttle. Replace that sensor and your good to go. Makes sense, right?

Check for vacuum leaks. Also try cleaning the ISV.


If that doesnt work go to vwvortex.com and post your issue there

Here is the most common cause of surges and stalls, it is the idle speed control air-bypass valve and throttle valve, they get full of gunk over the miles and cause idle issues (stalls) like yours, Get a can of intake cleaner from any local parts store, not carb spray, intake cleaner, it is made by a company called CRC, remove the air intake hose to the engine, hold the idle high so the engine won't stall, then spray the can of cleaner into the intake while keeping the engine running, use at least 1/2 the can, shut down the engine and disconnect the battery for 5 minutes, then restart and complete a number of mixed driving cycles, town, freeway, stop and go etc., after a few days the problem will go away as the system will relearn to the clean intake.

run the fault codes
look for ambient temp sensor or baro sensor problems

many automobiles behave that way on a cold start, so you don't have to worry about it. just continue to rev the engine until it is warm!