Well here is my headache. Back in Feb this year I had my OEM exhaust replaced due to the fact it had a leak. So since an OEM exhaust ain't cheap I went aftermarket. Car ran smooth. Now in July I get my CEL on my dash so I pull out the scanner to get a code P0420 (Cat threshold below) okay so I do my homework and replace both O2 sensors and that seemed to solve my problem... BOOM 2 weeks later. Now we in August and decide to book an appointment at a shop that ONLY work on Honda's and Acura's and is HIGHLY reputable for this thursday (aug 27) but notice on sauturday my car was kind of stalling and vibrating. It calm down until today. I know lastnight I installed my new CAI and replaced my Vtec Solo filter and all was good. So Im in my garage makin sure all is good and had the car running. Check engine light pops up so I scan it. This time around I get 3 codes.
P0420
P1491 EGR valve lift insufficient
P1498 EGR valve lift sensor high volatge

My question is what is causing this headache? Do I have to worry about my car actually shuttin down in the middle of the road? I see my rev goin a lil above 1000 but the drops down. My idle is low. I still have my appointment at the shop but Im just tryin to get an heads up in advance. I read on some thread that an aftermarket exhaust can trigger off all three codes. All help is WELL appreciated.

prolly needs a new egr valve

Yeah I was thinkin the same thing. But I wanna take off the EGR valve to see if it needs cleaning but look like I have stripped one of the studs. Dunno how Im gonna get that bitch off. This is stressin me out my mind right now. Grrrrrrrr.