As title suggests whenever I start the car it idles super rough, it can stall when cold unless I gas it on and off, and misfires show on my torque app on all cylinders... once it idles for awhile it gets a bit better and at stop signs there is no problem because after driving the car its more or less ok although a misfire shows here and there... ... only when I turn the car off, then start it up again it idles rough again, not as rough as cold but...

It's a lot worse when the engine is cold is what I'm saying...

Is there anything I can do myself to diagnose the failure point?

What would cause all the cylinders to misfire? Not a bad spark plug wire and not a single bad ignition coil because I would need all wires and all coils to be bad correct?

I'm not even sure where to start but perhaps with your guys help I can check a few things even though my skill level is rank amateur... I generally know under the hood what most stuff is per say so if you tell me to look at the so and so I could likely find it...

 

If you know where the Mass air flow sensor is clean it with CRC MAF cleaner. same goes for your throttle body, only use throttle body or carb cleaner. Also unhook the battery for a bit.

 

Only have about 10,000 KM on the MAF that came with the Cartuning Turbo kit so I would guess it's still clean.... I'll check it of course but any other ideas?

update - did a few cold starts(no MAF cleaning yet) just now and it finally threw a code after all this time.... p1400 .... and p0300... whatever is happening its getting worse!

 

Might be possible you have a bad maf might want to verify fuel trims to see how out of whack they are first.

Also double check your boost lines and waste gate lines for damage

 

does unhooking the battery for an extended period cause any custom tuning on any level to be wiped out?

Also, does anyone even know what MAF sensor is included with the cartuning turbo kit cause its definitely not stock? What exactly should happen when I unplug it while the car is idling because I did and nothing at all happened?

 

Check for cracked or bad vac lines as well. Any hissing sounds from under the hood while it's running? I think the car would sputter with the maf unplugged?

 

No it won't effect your tune. And your car is probably setup to use VE or virtual VE tables under a certain RPM (stock is like 3k). It should throw a check engine light however.