possible parts missing??

I just purchased a 1989 suburban. Due to a small hick up in the performance I was researching the throttle body injection set up. The info I got states that the engine should be equipped with a large distributor with built in coil. Mine does not. It has a seperate coil that doesn't look like an add on. The fresh air tube that leads to the air cleaner is missing. I understand that this should lead to the front grill or to the fender? If any one has any info on this I would appreciate it. Im having a miss a stumble situation upon a slow take off that I trying to diagnose and Im concerned that the engine set up is not accurate. Thank you Brian