i'd be checking the engine to body grounds. did you replace the right ect ? there should be 2 one gage one computer. sounds like you've swaped out everything else. check the intake gaskets for leaks. an injector cleaning might help. oh yeah get your alternator checked!!! when they have 1 or 2 diodes burn out they still charge and put out the right voltage but the ac spikes can cause some wierd things to happen with the sensor outputs. if non of this works get some good insurance and leave it unlocked with the keys in it!!! good luck