Chevrolet: beretta dies after warm up, crankshaft sensor, prom chip

Question
Thanks for the quick answer. When I got the new ecu we put the original prom in it. Could it be the Coolent temp. sensor sending a bad signal to the ecu or maybe a O2 sensor sending bad info? But again I'm not getting a check engine light and it runs great for the first several minuets. It is acting like a bad vacuum leak but only after warm up.

Shane-------------------------
Followup To
Question -
Hi Keith I hope you can help. I have a 1988 beretta with a 2.8 and automatic it has 105000 miles on it. The car would die going down the road after about ten miles, it would be running fine then just shut down. I did get a check engine light for the crankshaft sensor. I replaced it and still got a light I can't rember the code but I was told to replace the ignition modual, Still had a light so we swaped out the ECU finally no light. I did a compleate tune up and the car starts and runs great for about ten minuts then the idle dies down to around 200 rpm and bounces back and forth between 200 & 500 rpm I was thinking it was the egr but from all indications it seems ok, moves freely and when the engine is running if you press it in the engine wants to die. It will still drive and runs ok while putting the gas to it but it will die at every stop. I cant find any vacumm leaks and it seems that just about every sensor in the car is capable of making the car act this way. But if one was bad wouldn't I get another check engine light? The dealer wants $240.00 for a new egr but I dont want to just start swapping parts to find out I'm wrong. A new egr from the dealer is about half what the car is worth. any advise will help. Thanks Shane
Answer -
Hi Shane, I would say that the ECU you put in is not an exact replacment, pull of that little cover on the ECU and swap the prom chip it will probably work fine then. Let me know if you need more help. Regards, Keith.

Answer
Hi Shane, your right, replacing unneccerary sensors will cost you a lot money for nothing. There are certain anlizers that you plug in and with the engine running you can see the voltage values that the sensors are sending, this way you can tell if the sensors are working properly or not. The one that we used is called "OTC Gensis" it will show you all the info from the sensors if there is one thats not working properlt you can see it. I hope this helps you if you need more info just let me know. Regards, Keith.