I replaced the 1.8L motor on my 97 Miata with what I was told was a 95 model. I swapped over all parts that may have been different between the years to include the entire intake set up, coil packs, cas, crank trigger. The car starts up easily but idles very erratically. Cold start ups idle at about 1500 rpms but drop quickly to about 1000 rpms and then the motor kinda wanders up and down from there until it stall a few minutes later. I can keep it running but giving a little gas. On warm start ups it stalls right after it starts. If I gas it for a few minutes it will stay running but the idle still wavers up and down. I can not find any vacuum leaks or connectors disconnected. Also all connectors have been treated with electrical dressing. Oh one more thing it seems the fuel pump is making more noise but I am not sure since I took out the rear deck carpet.