So I got an A4 1.8t that is having some issues and I know this issue has been discussed on multiple threads. I have done quite a lot of research but still not clear on few things. Would someone be able to help me understand and then hopefully i can fix the car.

So i dont have a diagnostic scanner yet but will be getting it scanned somewhere very soon to see was codes comes up. Some of the issues i have been having for a week now is the CEL is on but on the rear occasion it will flash on/off few times then stay on again. Its also idling rough on cold start and intermittent misfire. The car seems to be fine while driving. I need to narrow down the search and eliminate some possibilities. I have replaced spark plugs and cleaned the MAF sensor. The MAF sensor made no difference to the car running whether its plugged in or unplugged. So is it good or bad? I had a quick look for damaged hoses and check valves but found nothing yet. Will have a more thorough look over next couple of days. I seem to think the problem could still be with the Vacuum system but still have to eliminate other possibilities like fuel system, turbo system and ignition. What simple tests can i do at home to isolate the issue. The oil cap has got a little bit of suction when i remove it but comes off easy enough. If u got info or point me in the right direction, I would appreciate it.

If possible when referring to specific parts could u also provide the part numbers or some reference. This is to help me distinguish the same same but different parts.

 

I just replaced my camshaft position sensor as I had a code for it. First start was beautiful and when I test drove it, it finally had the power it’s been missing since I got it. Spinning tires like nothing on a damp road and all. Basically just ran like a champ. But then I was going to the gas station and it started misfiring.... obviously not happy about this. I thought maybe it was breakup but nope, got half a tank and it still does Kodi nox it.