Chance

Put on a Greddy Power Extreme yesterday and a Walbro at the same time to take care of fuel. Already removed the cats. Every time I attempt to start the car, it doesn't do so on the first attempt. Just cranks. On the second attempt, it starts up fine like it always did. This happened to a friend of mine also on his jeep and he was told it was normal for it to do that for a few days. Sure enough, after a few days, all was fine. This doesn't make sense to me though. Did I possibly do something wrong on the install? Maybe missed something? Suggestions?