Could not find the other thread that I had posted to but this one is the same subject....I got my intake manifold gasket replaced for 210 (I'm lazy) the part is 50 so you could really save some money on doing it yourself. My syptoms for my 99 Honda Passport were the whistleing engine along with the CEL light on. A computer diagnostic for the CEL showed misfires and O2 sensors problems. The idle was always rough from 200 RPMs to 3,000 RPMs and would even stall right after starting. After doing all the reading on these Forums, I went ahead and got the gasket changed. EVERYTHING IS FREAKING GREAT NOW....Thanks for info and replies and this whole forum...it saved me from a Mech who wanted to start at the top of the engine and work his way down replaceing all seals!!! I told him no....just the manifold intake gaskets...