I have a 2001 Jeep Grand Cherokee and it has a really bad miss. I got the code off the Jeep and it said something about a leak detection pump and I was just wondering if that would be making it miss.
By leak, it means that the intake manifold is leaking and messing with the MAP sensor. The MAP tells the load on the engine by sensing the pressure in the intake. If there is a leak, it will not be able to adjust for the right amount of fuel, possibly causing a backfire if its too lean. The sensors are relatively cheap, but fix the leak first. It will be hissing like crazy.