A friend of mine bought an 01 GS that had quite a bit of work done to it and had a bad tune on it and fuel pressure problems to boot. After sorting out the fuel pressure it was time to start tuning and get the fuel trims back where they should be. After an initial maf tune and VE tune I drove the car for a while only to find out that for no rhyme or reason the pcm will go to +16.4 lftf. Again this is after maf and ve tuning and fuel trims were near zero at all times, except when the pcm goes into its fits. This can be just after startup, cruising down the highway, coming to a stop, it really doesnt matter when it does it, it just will and is random. I tried a complete pcm rewrite with a stock file, went out and did a quick maf and ve tune and it still acts the same. No codes and all sensors are doing what they are supposed to. The 02 sensor fluctuates, plenty of cross counts when this problem pops up, then obviously the car runs pig rich and will stay that way for an unknown time but normally no longer than a minute and then things go back to normal. Anybody have any ideas or have run into this before? Our next step was to try a different pcm but I dont have any of the correct code pcms on hand to try so until we find another one the car is being driven as is.