Your taking a big chance on doing the job again using the old gaskets. If you used a proper torque wrench. I would say you didn't get the gasket surface clean. Clean bolt holes if any silicon sealer was used.Look real close at the plastic intake it may be cracked. Watch bolt length closely as this can cause big problems. I have had to use washers if my used supply of bolts was slightly longer than the defective bolt. Before tearing down check closely for a missing bolt.
Proper cleaning takes a while if you don't have an air buffer which uses sta- brite pads..