Before I scrap this thing...

[KC9LDB]

I just want to see if there was anything else I could do that would work to get it running good again. The one problem is the P0420 code, thats just the cat, and it was running decent today, ive had that code for a long time. But heres what happened today, I was in my garage, I installed a external breather for the oil and plugged the port on my aftermarket intake. (the black hose that plugs in right by the throttle body) I revved it up to 2900 then to 3200 and kept it there for 15 secs just to see if there were any leaks or anything, when i brought it back down, the engine sputtered like no tomorrow, ran terrible. I made sure everything was reconnected and shut it down and fried it back up, I revved it back up which took longer then usual due to sputtering and the service engine light started flashing with trac off. I then scanned it and it gave me a multiple cylinder misfire and the obvious low catalyst efficiency code that ive always had. So i disconnected the cat, sputtering went down termondusly, checked the plugs boots, module, coils, and it stayed the same. So right now i have the engine giving me a gassy smell, some of thats due to the cat being off, and it has a heavily rough idle, I can bring it up to 3000 and it runs smooth, just loud as hell but when i bring it down, it shakes everything.
What else can i do?

[DOHC_tuner]

do a comlete tune-up before you give up. i strongly recommend changing your coil pack housing. Dont just test it cause it will test good, CHANGE IT. Also change your sparkplugs.

[KC9LDB]

yeah i took care of that already, im running out of options

[GA_turbo]

did you happen to disconnect the map sensor at all, just wondering im trying to help you out too. check your tps sensor also.

[KC9LDB]

Alright Ill check em tomorrow, thanks man!, I have no clue what would happen if i had to loose this car, ive had it since 35000, basically when i got my license, only thing i drove.

[DOHC_tuner]

yeah i took care of that already, im running out of options

okay so you replaced this...just making sure

http://www.autozone.com/images/products/wl2/wl2cb9003.jpg

[KC9LDB]

yeah thats correct, now I question the coil packs and do i have a egr valve? I couldn't find anything about it when i looked up parts for my car, its the LD9

[DOHC_tuner]

aleros dont have EGR's....now the coil packs are expensive so just go to your local junkyard but take some string and baggy pants. Tie the coil packs on your belt inside your pants and dont forget to pretend to buy something

[Spilner521]

aleros dont have EGR's....now the coil packs are expensive so just go to your local junkyard but take some string and baggy pants. Tie the coil packs on your belt inside your pants and dont forget to pretend to buy something
They're not that bad. I got an entire IDI cover with the coils and ICM for $50 form a local junkyard.

That would be pretty funny though. "Is that an LD9 coil pack in your pocket or are you just happy to see me?" :p

[[ion] C2]

do i have a egr valve?
some rare 1999s had EGR

[KC9LDB]

DOHC_Tuner, i think you fixed it, my coils are all at good normal readings, plugs, boots all fine, module tested good, that leaves me with one thing, and how did i find this out? My friends 2.4 grand am, just swapped the covers!