Lack of throttle responsiveness after header install
 

Hi guys
I installed an FT86SF UEL Catted header yesterday and found that the throttle feels less responsive at low speeds. Trying to get the engine up to speed in order to get my car moving takes a lot more input than before. We had found a leak from my Perrin 2.5inch midpipe to the frontpipe but fixed it. Any suggestions as to why there’s a lack of responsiveness?

Did you get a tune to go with that install?

No I have not, planning on it soon, I’ll need a custom tune though as I have a CAI

Likely the tune is exactly why the car doesn't feel right. Let us know once you get a tune.
Are you also saying you have a cold air intake on the car as well with no tune? Or is it tuned for the CAI?

I've swapped a heap of headers and never needed a tune, I would check your wiring.

Dirty or damaged O2 sensor?

Was it running fine before the header but after the CAI?

Yeah no tune with the CAI. I’m running the Grimmspeed so the MAF scalings are very similar to stock.

Actually running fine after the CAI but before the header. Went CAI first then catback then header

I would first check the 2 O2 sensors wiring and connectors.

Did you use anti seize on the O2 sensor thread?, maybe you got some on one or both sensors.

Has it thrown a code yet?

Didn’t use anti seize. Cleaned off the threading when reinstalling into the new header however. Hasn’t thrown a code yet and all the wiring seems to be fine. The car runs perfectly fine and pulls well, it’s just that the throttle feels slightly less responsive than normal.

Probably during installation battery was disconnected, and thus ecu needs some time to relearn throttle pedal's travel & fuel trims. Search around/google for dead pedal fix and shiv's reset.

Actually did disconnect the battery now that I think about it. Will try the dead pedal fix and let you know. Thanks for the help!

It takes 50 miles or so for ecu to adjust