alright i was wondering if anyone knows what size fuel injectors where on the 89 Prelude si's ??? and another question is what would cause it to idle at 4,000 rpm....by the way nothing is done to it. STOCK!

 

forgot the injector size, but about your ideling problem...
It could be one of many things...
vacuum leak...
coolant needs to be bled (try this first)...
fast idel valve needs to be cleaned...
intake manifold or TB gaskets leaking...
Check http://www.preludepower.com under the 3rd gen section for more help