Almost all modern electronic cars shut off the A/C during WOT only. Most are just a simple switch activated by the TPS/APPS though it only sense WOT and shuts down the compressor then. I don't think this is the OPs issue though. I think he's got a leak somewhere.

 

Actually the PCM is what engages the AC compressor and can delay operation for up to 30 seconds.. it will turn on or off depending on the various inputs to the PCM. Inputs include APPS, Transmission temp sensor and transmission gov press sensor, also the HI and LO press sw's. So I guess it can turn OFF the AC compressor if it decides to.

I agree I don't think its PCM related, its either a recharge or dirty rad/condenser or eng cooling fan hub.