lil eric

first off, this problem is in my 96 camaro daily driver. It has a LE cam, long tubes and supporting mods. PCM was tuned for these mods as well. the car will start and run fine for about 15-20 min until it gets some temp in it, then it spits and spudders and back fires and finally wont run at all. the only code i get is the P0372. it had a fairly new MSD opti, only about 2mo old. i figured it went out so tonight i swapped in the old opti that had been in it and running fine. still same problem. i have also changed the coil and ICM.
i have checked the wires to the PCM from the opti and all are in good shape with continuity to the PCM.
Im open to ideas at this point, ill be sending the MSD back to have it checked and fixed tomorrow if it even has a problem.
what are the ods that both opti's have the same high res signal problem? its not giving the P1371 which is more common i though.
thanks in advance, eric