need some suggestions for my warm up idle problem...thanks

ever since i installed my veilside type intake manifold my warm up idle has been all messed up. before when i had the factory manifold on, the rpm's would start at around 1400 or so and slowly drop to around 650. now when i start the car up the rpm's are immediately at 650 or so. what could be the problem? the only thing not hooked up the same way is the sub- throttle position sensor. i have it disconnected because my 100mm throttle body that came with the manifold doesnt have anywhere for it to go. in case it matters, im using a g- force ecu with a vpc. what could be causing this idle problem? thanks.