[Tectoniic]

Slow your roll a bit and let's do some of the diagnostics that other people have mentioned. The dealer may have told you they couldn't get any codes as they might be codes related to the powertrain and they think your mods are the fault and don't even want to open up that can of worms.


1. Get an OBDII reader ( or see if autozone or similar store will let you use theirs) and see if you can read the codes for yourself.


2. If you get some codes google them and that will make this a hell of a lot easier and save you time and money if you go to the dealer with a decent guess as to what the problem is


3. Just because the seller didn't say there was a tune on it does not mean there was actually not a tune. When the dealer reflashed your ECU to stock it is no longer accounting for your intake and header. This could be causing you to throw lean/rich codes or some other kind of general cat converter code. I am not familiar with the agency headers but if they are catless this is probably your problem.


4. These codes could possibly trigger limp mode as the car thinks it is too rich/too lean and trying to protect itself. I wouldn't try it until you have tried to read codes with a scanner to make sure it is not something that you will damage by revving the engine but if you can rev past 5k then you know it is not limp mode.


5. If you find out it is just a cat efficiency code then all you will need is a tune to account for your mods. There are plenty of reputable tuners on the forums and I know people like Delicious Tuning, especially if you need a quick solution.