I posted this on rx7forums, and I know its hard to diagnose without actually seeing in person, but thought Id make an attempt and ask here. Im just going to paste my other posts,,



OK, well I took my UIM off the other day to swap to one that I had painted up all nice and pretty Anyway, when I put it all back together, the car wouldnt hold an idle. It would just start, then die. I could give it gas and keep it running, but it was running very rough below 4k and backfiring when i let off the gas. I re-used the old manifold gaskets, so i just figured that was the problem, it was leaking around there. So I ordered new gaskets, they acme in today and I took it off and replaced the gaskets. It is still doing the same exact thing. Heres the weird thing, if i rev above 4krpms, there is a fairly loud "whistle" coming from the engine bay somewhere. It gets louder as the rpms climb, and I cant hear it below 4k. I know this sounds like a vacuum leak, but I am 99% sure there are no leaks, as Ive taken the manifold off countless times, I know what Im doing. Does anyone have a clue as to what this could be, or maybe an area leaking vacuum where I could have overlooked? It will not idle at all... Thanks

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Ok, Ive taken the entire IM off and reassembled, checking every line and making sure everything was ok. It is not a vacuum leak. I think its a problem with the TB butterflies, because it only whistles when they are open above a certain point. What would cause this, and make it not idle, I have no idea? Any Suggestions? Its not a faint whistle that you have to listen for, its very loud. Any help would be appreciated

 

what exactly do you mean by "whistle"?....if it is not a vacuum leak then your throttle stops and/or idle speed are too low





95% of the time its a vacuum leak, Is the inlet tube on correctly? Did you forget that 0-ring that is on the front of the throttle body? I've dont that and chased my tail for an hour

 

It friggin whistles, like "wheeeeeee" real loud, seemingly coming from about the TB. Yes inlet tube is on correctly.

 

have you tried putting your old intake back on? i think its a vacuum leak too btw, and it was something you did too, cause you say it was fine before



mike

 

did you check the screws inside the TB @ the butterflies?

 

whistle?





sounds like a vacuum leak to me, unless somebody secretly pyut a whistle tip on your car.