Ok heres what happened: I crank my car up and drive to the shop literally 1/4 mile from my house where my friend works,leave my car running there for 30 mins appr.,Get back in my car (temp about 220)get on the road and notice it's a little sluggish,get on it like usual and falls on its face then.......BANG......it back fires,wholy $#!^!!!! I turn around and ease back to the house,take it out of gear and rev it up about 1/4 throttle....no problem....hold it .5-whole throttle and it runs like a trd and whne it is running bad you can hold it from an idle and it will go to about 2200 rpms and stay there and pop and bang and smoke and act all kindsa crazy,you let off the gas idles with no problems try to give it any gas and it runs horrible you give it a little bit of gas but get it up in the rpms and....well its like a carb car like your having to clean off the plugs! It only does this crap when its really warmed up but when it's cold then it runs almost normal just minus about 20 hp. Like I can let it set until the temp is completely down and go make a pass (without having to wait in line) and it will run like a 9.40 if im lucky(car usually runs way low 9's or high 8's)make another pass without stopping and itsa about a 9.60,do the same again and its about a 9.75-9.80,go back and park it for about 5 mins then go back up there. And you cant even do a burn out!!!!!!!It does just like I described. So what the &%^*??????I dont know I am extremely new to the lt1 but have got a few suggestions,the most popular is an 02 but all of my o2s look fine on the scan tool except for that my bank 2 sensor 2 is reading about 50 lower than my bank 1 sensor 2 but from what I hear the o2s after the cats have notta ta do with lean/rich or anything like this. another suggestion is the coil wire or the opti( I sure hope not). The weird thing though is thatit is not showing any misfire codes and the only 2 codes it is showing are low cat efficentcy bank 1 which was on way before this problem and secondary air which was also on way before. crazy. Another thing is that if you watch the data stream on the scan tool while you are going down the highway then the timing is advancing up to 20 degrees at times which I thought to be very high! Anywayz sorry for the long post but please help me!!!!! Any suggestions are greatly appreciated!!!!!

 

as far as the timing the most i've seen mine advance was 10 degrees,,,i had a 96 z28 and when the opti went it ran like **** all the time not in spurts like your is doing,,,,,,,,,

 

Really!! So do you got any suggestions on what it might be?

 

i had a 95z28 with an auto and one day it started running like crap would not shift out of 2nd because the rpms would not get high enough thought tranny was shot got the my shop that I work at and found manifolds glowing I had had a vacuum line leaking at the intake and causeing the engine to run lean for some time and lean creates heat anyways the cat was shot clogged so i got rid of it thats cause i live here in florida and the car ran fine except for it would bounce off the rev limiter so i replaced the coil wire and car ran fine ever since

 

well my fuel trim #s are fine so i dont think that a vacuum leak is the problem but I have been leaning more and more towards it being the coil or more likely the coil wire. Does this sound maybe like it may be it?