i was doing a run...and i topped out 1st gear and i changed into 2nd...when i did that my afr gauge like went all the way to lean and the car almost cut off...now the car sounds like a subaru and it doesn't want to go anywhere

melted piston?

 

compression/leakdown test time. somefins broke *****

 

yeah we're gonna get drunk and do the compression test tonight...lol...if the motor is bad i have my other ls sitting there we can swap in...and if that ls goes in...it's time for me to go turbo again

 

mine did that once, check you injector clips. that was my problem. or your pulgs and wires first.

sounds good eh?!?

 

basically you have a cylinder not firing...could be loose wiring at ecu/harness, injectors, plug wires...

or it could be a cracked sleeve/melted piston

 

Trust me...you'd know if you had a cracked sleeve on boost...been there. When my sleeve took a ---- it pressurized the cooling system and shot all my coolant out the overflow like a pressure washer Pull the dipstick and smell the oil...if it smells heavily of gas (most of the time it does, but not always) you probably torched a piston

 

mine is all motor for now...compression test was 220 across the board on my ls...we found out it was a plug wire prob.

 

sounds like you blew a headgasket. Out of my experience, when my car sounded like a Subaru STI with open downpipes. My engine blew a headgasket and there would be tons of white smoke coming out the muffler. Good luck