Alright well I just sold a friend my bone stock b18c1 engine with 52k on it. Nothing was wrong with it when it was sold to him. Well before we did the swap we changed the stock b18c1 intake manifold with a skunk2 intake manifold. We changed the intake manifold gasket an scrapped all the old gasket off before installing the new one. We ran in to some issue's with the stock gsr tb so we used a b18b1 instead. Well the motor is currently in the car an is running. This is the probelm that were having below.

1. Car starts up an idles at about 2k then drops to 1,500k then back up again. We checked for leaks around the intake manifold gasket. We checked for leaks around the tb gasket. Still cant find a bad vac line that could be possibly leaking. Change iacv valve an still same thing. Map sensor an tbs sensors are in good working condition. Now when I block off the fitv with my finger the idle goes back to normal which is 800rpms. Could it possibly be the fitv? I already tried the starting fluid trick to trace leaks an havent found a thing.

Can someone please help me out. I been working on honda's for five years now an never had this type of probelm before.

 

its something with the fitv. or you have a air leak somewhere else. do a leak down test and see what the results are.

 

wouldn't it be easier to just clean the fitv rather than do a leak down test? 3 bolts and 2 screws, brake cleaner, and about 20 mins. and your done.