OneBadTA

My trans am was off the road and torn down for the past 3 years and finally got back to putting it together. Replaced headgaskets, water pump, opti, seals, plugs, wires. Also deleted AC and EGR and installed some Long tube headers. After all said and done it fired right up, put some fresh 93 octane and fuel cleaner in and started to drive. When the engine is cold it has a very noticeable misfire but once the engine reaches operating temp of 185 then the misfire completely goes away and runs smooth as can be. I am running open downpipe at the moment and have 14" dumps coming off them so unsure if the O2 sensors are being effected by it. What does everyone think? Does the LT Headers and EGR delete mess with air fuel ratio that much before the O2's begin to monitor?

FAD2BLK93

Is this car tuned for the changes u have made? Sounds like it may be lean at start up befor closed loop. Can u look at live data? Are there any codes?

robsquikz28

iTrader: (246)

u need a pcm tune

OneBadTA

It's still on stock tune. Havnt drove it to check codes but at idle it throws the egr and ac code. I figured it was probably the headers throwing off the AF needing a new tune. I'll drive it and monitor just to see if other codes come on.

OneBadTA

Drove 10 miles and the only code thrown was the EGR code. Code 37 i think it was. So far it sounds like its only a computer tune needed.