I have a rusty old 96 Magnum 425 4X4 I rebuilt from the ground up. The last part I put on it was a new carb. Now when I start it she fires up perfectly but like many others, I go over 1/3 throttle and she starts to sputter. If I have the choke on she is fine, just idles higher, but the sputter pretty much goes away. Before I rip the carb out and check the jets, could this be a choke issue?