Long story but i bought a 98 trans am LS1. 116k. Has a small cam, previous owned did not know exact specs. Anyways. He bought it with the cam. Tuned it. Fixed some things. Egr delete. Turned off knock sensor that the can was setting off. Turned off downstream O2 sensors. Now. Since ive gotten ahold of it. I drove it roughly 700 miles home and it didnt kick a SES light until after having home about a week. Low rpm kicked a random misfire which he said was from the cam. Anyway. I have done all plugs and wires. Ngk 55s. Longtube headers. Since it still had its factory exhaust. Big exhaust leak. Anyways finished all that today. Also torqued down intake manifold cause it would cold start and shut off. But on first start after all that. It sounded WAYYYY better. Much healthier sounding. Smooth and was much more thrittoe responsive. But shortly after it kicked the random misfire code. Could i be looking at a vacuum leak somewhere or perhaps fuel filter? Also all the plugs were factory acdelco and the gaps were all over the place. No oil on any tho and one was a ngk 55. Any suggestions would be greatly appreciated. Thanks

 

Sounds like the tune he did was fucked off and since you have more mods on it, it needs a re-tune. Making sure the Plugs are all identical is a good start.
Cam was not setting off the Knock Sensors, his bad tuning was. I have a healthy cammed 6.0l in my MCSS that idles and drives smooth as butter, again my proper tuning.

 

Update. I am not a tuner but as everything else ive discovered the information is out there. Just have to find it and learn. I ordered HP tuner WITH a wideband. I dont really trust a dyno tuner around where i am. As well i also pulled the plugs and changed them to the NGK6s with a .04 gap instead of the 55. Read too many people saying they are just better and IMO they are correct. Seemed to run even better. I believe it needs more timing down low still. Hasnt kicked a SES light. So a good start i believe? Im wondering if tune is bad as well like you say. Watching LOTS of goat rope garage and as many others i can find who seem reputable. If anybody is willing to help me understand more and learn. Which im doing to the best of my abilities it would be greatly appreciated. Also looking into if i have to pay for a tuning class to do it correctly i will.

 

I've seen misfire problems go away just by reducing factory spec .060" plug gap down to .035"

 

Too wide of a plug gap isn't a good thing, however too tight of a gap won't ignite as well.

 

Agree 1000%. Which i feel in my opinion it runs much better now. Not as rough and choppy. Kind of hard to explain. What worries me is he had lid on it and it did the typical pop the clips off all the time. Well i got an SLP lid for it and the correct plenum for it so its on their tight as ballz IMO. Also did have the longtubes obvi. Changed location of the upstream O2s which from what i understand the computer needs to know that? Just worried my ears and eyes of what the car is telling me isnt true and that perhaps im doing harm more than good. Which is why im almost scared to drive it without a tune. Also the guy who sold if to me is super communicative still. He actually talked to me lastnight for a hour about it. Hes hella intelligent compared to me. I just want to do things correctly. Which is why i bought hp tuners and the wideband. Want to do right by the car without ruining anything.