[veethe335]

hello everyone! i am new to this forum so might ask already answered questions..

so i removed ceramic (substrate) monolith the stuff that is inside the cats, to make exhaust sound batter... i didn't eliminate or installed O2 simulator..
when i start the engine it idles fine, maxisys pro shows no codes. after couple of miles my vehicle shakes when on low rpms. 10 min past it starts misfiring.
after i resent the computer misfiring goes away . vehicle idles normally again.

so my Q? is it possible that the misfiring, runs like crap: because of catalytics substrate removal which causes air to fuel mix, or something else? and I'm only getting 5 cm of boost:/
please help!!

[Boosted2000Si]

Did you install the o2 sensors back in correctly? The one with the metal heat shield should be the top one.

Make sure they are plugged into the correct plugs too.

[veethe335]

yes they are all installed correctly. i tested my o2 sensors: pre cat wave form is lean on graph, voltage between 1.7-2.0 V. post cat zigzagging between 0.1 to 0.8 V

Multiplicative mixture adaptation: -8.64% Multiplicative mixture adaptation 2 : -6.65% (when i step on the gas Multiplicative Mixture Adaptation:increases to about 20% and MMA2: decreases by 1%)
Additional Mixture adaptation:0 mg/stroke.
Q what do these last three values stand for? and are they within the normal range?

[veethe335]

found a solution to my issue. the injectors had to be cleaned. now it runs and drives smooth.
i found this forum very Helpful:/