check this out

ok… .I did a engine and tranny swap. now when the engine is cold the car will start right up and idle around 2500 rpm and once it gets to normal operating temp and I cut it off it won’t start again. I took the a/t box from under the hood out. would this have anything to do with it? I have checked fuel and spark and it’s getting both. how much voltage should be coming from the end of the spark plug wires? any help would be nice.