we are running a 89 beretta with a v6 and once it reaches 130 to 160 degrees and above it will start beaking up unless you throttle it very slow and even then you can onlu throttle it 3/4 of the way. we did just rebuild the engine but it did it with old engine also. it has a 3.4 block punched 20 over with a 440 cam and 2.8 heads and intake and pletuim. but like I said it did it with old motor also wich was 3.1 block stock cam and 2.8 heads and intake. we have replaced the computer / ign module / all coil packs / plugs and plug wires / fuel pump with a bigger fuel line. when the car is cold I can tach it up 6500 easy but once it hit that temp 130-160 cant even get it to tach 2500 with out it breaking up. I have tryed unplugging the coolant sensor and o2 sensor to throw it back into open loop but makes no differance. I have also unplugged the fuel regulator and make no differance. Any ideas? plz help Thanks