GOt my b16 with bolt ons and stage 1 cams tuned last year with a vafc 2......I had a check engine light due to my lack of a secondary o2 sensor...the one after the cat......now, i decided to pop on in and i feel like im a lot slower.......my drivability is much better...i have a lightenned flywheel and stage 2 cluth, and without a seconday o2 sensor, my car felt more free flowing but harder to drive, i had to rev a ot higher to move...now with the 02 my gas is much better(milage) my deivability is better but when i gas it, it feels slugish from lower rpms maybe im running to lean thats what it feels like...It feels like something is blocking my cat, very restrivive feeling

 

itr ffatory header ,high flow cat, 2.5 inch piping apexi exhaust.....so, i doubt it can be the flow....casue im pretty unrestrivive,

 

Check the abcs... tune up (cap , rotor, plugs) Sounds to me like a spark problem. Check how good your coil is.... Pm me if you need somebody to look at it for you. I dont usually charge diagnosis time.

 

i dont think its the basics cause the car was running amazing yesterday, its only after the secondary o2 sensor was installed if i remove the seconday o2 now, the car will run perfect, but ill get horrib;le gas milage.....from 500 hm a tank to 370..

 

ditch the vafc and get tuned properly. it will make a difference far beyond what you think.

 

Word, go obd1 and get it tuned with crome.
You won't need to worry about secondary o2 sensors anymore. Hell for that matter, you won't really need to worry about o2 sensors at all anymore....with a good tune.
WeiRtech knows first hand the benefits of a crome tune over a vafc. His car hauls a$$ and he says it runs way better now that he's had it tuned with crome compared to when it was running off the vafc (no check engine lights, no stuttering).

 

well yoru obd II computer is now finally being able to adjust your A/F by 02 sensor...therews is closed loop and open loop one reads when your o2 sensors aren't warm yet it reads off tps map etc then the other reads off the 02 sensors..

so you got you **** tuned with a obd II comp without the computer workign properly now that it's proper it is runnign the **** tune...get it tuned again.