Underdrive pulley problem

[RAYZ02GT&93LX]

Before I came home form the shop tonight I figured I'd throw on my set for march underdrive pullies on the 02 gt. I got the set with the SFI balancer. Now heres the interesting part on the way home cruising speed low rpm's no problems, but if I get on it get up to 4000 and 50+ the car takes a shit. Check engine light flashes which is real bad and the car misses like crazy. can underdrives throw off the factory computer that bad does the car need tuned just for a set of pullies? Im realizing why I like 5.0's more than modulars. Any insite will be appreciated. I forgot to mention Two weeks ago put on accel super coil COP'S no problems in the last 2 weeks until I put on The underdrives

[Ares]

Are you positive you got the dampener tightened all the way down and to proper torque spec? The timing wheel is held in place behind timing cover by balancer and if that is not on properly. Check any wires you may have unhooked by chance. Won't need tuned for pullies.

Also try resetting computer. I've seen odder things happen. Other than that I never had an issue with pullies.

[John4cam]

So it's not the piggyback style?

[RAYZ02GT&93LX]

No I bought the SFI kit. I heard bad things about the piggyback style. Ill check the dampner tomorrow. I was thinking about taking it all back apart and starting from scratch. It was getting late and our special tool section is a mess couldnt find the installer and the later it gets I start to rush. I guess the flat rate state of mind isnt the best one when you are doing performance mods.

[John4cam]

No I bought the SFI kit. I heard bad things about the piggyback style. Ill check the dampner tomorrow. I was thinking about taking it all back apart and starting from scratch. It was getting late and our special tool section is a mess couldnt find the installer and the later it gets I start to rush. I guess the flat rate state of mind isnt the best one when you are doing performance mods.

Did you torque the dampner down to what was in the instructions? I think on my buddy's it was 60ftlb's?

[RAYZ02GT&93LX]

YES EVERYTHING IS RIGHT ON PULLIES. MARCH SAID THEY'RE PULLIES WOULDNT DO THAT ITS EITHER THE AFTERMARKET COILS OR SOMETHING ON THE TRANS. GOT IT TO DO IT AT WORK SO i CHECKED WITH IDS GOT A MISSFIRE CODES FOR 4 AND 7. SO I ASSUMED IT WAS THE NEW COILS. PUT THE STOCK COILS BACK IN AND ON WAY HOME IT SSTARTED AGAIN THIS TIME IT SET THE CHECK ENGINE LIGHT ON STEADY. CHECK WITH MY LITTLE MAC SCANNER AND IT WAS MISS ON 4 AND 7 AGAIN BUT WILL DRIVING I HAD A TRANS SOURCE CODE PROBABLY CAUSE I PUT IN MY GEARS AND DIDNT REPROGRAM THE PCM BUT ALSO HAD AN EGR CODE. SO IM GOING TO LIMP IT TO THE SHOP TOMORROW AND PUT IT ON IDS TO SEE WHAT CODE I GOT. THE LITTLE MAC SCANNER DONT GIVE YOU EVERYTHING.