Exactly what do you mean by "real touchy"? Is it irritable? Does it walk away from you or make sarcastic comments?
You need to describe your problem in detail. i.e. Does it seem to crank at normal speed but not fire? Does it crank slower than it should? Is it intermittant? Problems when it's cold, warm, etc? Did it start happening immediately after the battery swap? Have you checked the battery voltage when you're having the problem?