My car went into limp mode the other day driving home. Poor idle, little power,vsa light on, smelly fuel rich exhaust and shuddering are symptoms.
I've replaced the maf and iat per the high voltage cel codes. Still have problems. The turbo does spool up. I'm ready to throw in the towel and take it to a dealer unless anybody has any idea?

 

My last car did this because the coil went out. Pull your plugs and see which one is blacker then the others, it's worth a shot. I don't know if there's a way of testing a coil pack to see if it's functioning properly.
Also don't drive when the car is in limp mode you will destroy your catalytic converter, your first cat will get wrecked. Your not getting spark in a cylinder so your getting more fuel to try and compensate for it which is why there's a fuel smell.
Coil packs are about $40 each at AutoZone. You'll also need to get a new spark plug.

Good luck

 

Did yours throw the same cel codes as mine?
I haven't driven it. Just sitting in my garage.

 

No because it was a different car which will throw different codes but had the same exact issues. When your car goes into limp mode your car will produce more fuel then your car will try to give it more air but that goes to all cylinders which will throw a code for issue with air flow so you get MAF sensor sensor issue and so on.
If you can rule out those sensors going out I'd say coil pack or it might be a fuel injector got stuck open pouring fuel into a cylinder, like I said just check your plugs you should have one that's more burnt/ blacker then the rest. If they are all the same then you can rule out my opinion.
Take pictures and show us your results so we can better help trouble shoot.

 

Worked on the RDX today. I tested first by running the car with the number 1 cylinder coil pack plugged in, then unplugged.It didnt run any different.
took off the intercooler and checked the plug. It was fouled and fuel rich. I ended up replacing the coil pack plus all four plugs since I was in there.
Now runs like a champ! Funny how the car kicked off the air codes. Now that I think back, it did kick off a P0301, but I assumed it was just from the poor running.

thanks NautralFlavored!

 

No problem glad it was an easy fix for ya.
Glad I was able to help.