| Hi, I am having an issue with a small air leak which appears to be centered around the fuel injector for cylinder #2. When I pressurize the system with 1 to 5 PSI of air I can hear air leaking between the first and second branches of the plenum on the drivers side counting from the front. When it is fully warmed up and idling I can spray water from a misting bottle and every now and then hear the water being sucked into the engine and the idle drops down. I think I saw a piece of an O-ring around this injector that is broken off as well. Not sure how that is possible but I do not remember exactly how far the top O-rings sit inside the fuel rail. It is difficult to see exactly where the leak is but it does not appear to be coming from the plenum gasket. If the top injector O-ring was degraded so badly that air could be sucked between the injector and the fuel rail I would assume that fuel would be spraying out. Would a leak at the seal between the fuel rail and plenum connection cause allow air to leak while not causing a high pressure fuel leak? Thank you. Details:
It is a 1995 NA slicktop with 155,000 miles driven 5000 miles per year in Seattle where the climate is very mild - heated garage kept.
The car idles a little high at around 750 RPMs most of the time but sometimes it does get down to 700 RPMs.
Nissan DataScan shows the AAC valve with a slightly low value of 12.
When doing the active idle adjustment test within DataScan the idle will rise to 800. I can turn in the idle screw all the way and makes no difference with the RPMs when doing the active idle adjustment test. I also see in DataScan that the timing is being retarded to 7 or 8 sometimes during idle to try to bring the idle down to 650.
The valve cover gaskets were replaced two years ago by a shop - I had them replace all the under plenum hoses when they had the plenum off including the PCV valves.
The IAA unit was replaced a few year ago as well by the same shop.
I have never replaced the injectors since I have owned the car from 110,000 miles and I see no evidence that the previous owner did - there are certainly no dremeling.
The TPS is set correctly.
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