my car is iddling poorly, the rpms will drop to 300 and almost die and then it will bounce back to normal when stopped at a red light, it bogs down every now and then when taking off. no SES light, fuel filter changed couple months ago, any ideas? the car has 80k miles. any input appriciated.

also are the front and rear O2 sensors switchable, thinking the front O2 sensor may have gotten damaged when taking off cats.

 

I'd start with new sparkplugs and see if that helps.

 

Did you jack with the MAF? What else did you modify besides the cats?

 

lid, cutout, tune, erg delete is all i have done. haven't touched the maf since i put the lid on over a year ago. i am thinking plugs, injectors or an o2 sensor. no ses light but cant the computer throw "soft" codes that don't triger the ses light. should i go scan it for the hell of it.