hi guys, i just new to this forum, recently (summer) i bought a 01 Audi A4 1.8TMQ
car was fine but now is starting to making me some trouble.
the first time i make a tune up (1 week after i bought it) i changed:
*engine oil
*Air filter
*Spark plugs
* Transmission Fluid
*Cabin Air filter
*Brake pads
*oil filter
after a week the engine stared to shake so bad and CEL come out P0411,P0300, P0303 and P0304 so i change the 4 coil packs. after that CEL P0300, P0303 and P0304 where clear but P0411 still come back.
i check all PVC and vacuum lines, evreything is good and no licks. so i check Secondary Air pump (SAI) connect it direct to power and it works, no rust or water signs.
now after almost a couple of month same codes came out (winter time). P0411, P0300, P0303, and P0304. I noticed that when weather is below 30F my car does not make the normal start up warm-up and SAI does not start at all or start randomly even after 5-10 minutes of normal driving and every time SAI starts engine starts shaking like SAI is taking a lot of current, i seen all my light dimmed when that happens. please anyone has ever had the same problem or any information of how to fix it. thank you.

sorry for the log write up and for my grammar.

 

i have the same issue with the cold start problem, but mine occurs because the throttle body adaptation fails. i tried to use vagcom to do the throttle body adaptation, but it fails. after some time of letting it idle, i shut it off. turn to on position, hold the gas pedal down for 5 seconds, turn key off. then release the pedal and wait some time. then i pull key out and try the TBA again. sometimes it works, other times it doesnt.

 

once running how are your temperatures? Temp gauge in the middle? Get good heat? I had a similar problem with cold starting and was the coolant temp sensor that told the engine it was still warm and didnt need a cold startup idle or SAI help.

 

My cars temperature reads never goes past the middle, it is always increse gradualy at 1/4 or +1/3 but never at the middle. Keep in mind that is snow season always cold usaly 45F to -15F. So there is not reason to think it may be the coolant temp sensor. What I saw is the oil temp never goes up is that ok? And I thin I also have a worn out exhaust gasket the one that connects afther the turbo, can a blown gasket make my car behave like that? I mean by giving incorrect readings to the Co2 sensor?

 

I am going to try that and see what happens but I don't think that would some my problems. Thank you.

 

Temperature is good, temperature gauge never goes past the middle and i have good heat. i don't think i could be the coolant temp sensor but it may be if the sensor is dying and randomly working don't you guys think? how much does a coolant temp sensor cost?