So last spring I was able to burn the tires off the line, but now it can't do it anymore? Heres whats been done to it, new plugs, cap and rotor, ignition module, maf relays, tpis airfoil, new airfilters, ohmed injectors all at 17.2 +- .2. The only thing i can think of is when i checked the timing it was at 8 degrees advance, so i put it back to the stock 6 degrees, but i thought the computer controlled the timing with the esc hooked up. Shouldn't a 305 tpi with 3.42 gears and posi be able to spin off the line? I know my old 2.73 open rear would spin the tires forever

Does it run any differently? Did you get new tires? Headers? If nothing like that has changed, it seems like tune is off or the car isn't running right then.

Everything else is the same, I still have the stock exhaust, and the same tires. When driving it will downshift and rev up fine, it just doesnt seem to have any power. Sometimes it stalls when started warm. Maybe I should try replacing the coolant temp sensor?

ok so heres what i was thinking is probably causing this...

My y pipe is crunched under the engine and the pipe next to the differential has a big dent in it, and my cat is probably getting old.

My plan is now to save up enough money to swap in a 350 and do the exhaust at that time... shouldn't be too expensive considering i already have 2 low mileage complete 350's i can use. Should have this done by the end of next summer.