"05 Tribute "whistling" sound
 

'05 Mazda Tribute
4 CYL 2.3
139k. miles
Phoenix, AZ

Okay, here goes....

About 3 months ago, my wife's car developed a "whistling" sound. Unlike the few other posts that are even remotely similar, it only happens when the car is warm (normal operating temperature). When the car warms up there is a clicking sound (thinking thermostat opening) at the same time the "whistling" begins. When accelerating the "whistling" goes away (thinking vacuum leak). Aside from going away when accelerating, it gets louder the hotter the engine is (we bought it used with 60k and the car has not overheated while we have owned it).

I have tried carb cleaner to find the vacuum leak but it doesn't consistently give the same results. When it does give me a rise in RPM, it seems to come when spraying the lower front left hand side (drivers side) of the engine (again, it does not always give me the same results). I have tried taking the throttle body off and cleaning it, but no perceivable difference. I have a gasket kit for the intake on order (be here in a day or two).

When it first started, the engine would "stutter" when it was turned off (not every time, but occasionally and this no longer happens). Also, It would "surge" when idling for (again not every time, but occasionally and this also no longer happens).

The "check engine" light came on at in the beginning and at the time I got the following codes:
-P0301 Cylinder 1 Misfire Detected
-P0306 Cylinder 6 Misfire Detected *** as stated above, this is a 4 Cyl***
-P2195 Oxygen (A/F) Sensor Signal Stuck Lean (Bank 1 Sensor 1).

This morning I ran to Autozone to get the codes read again and got:
-P0107 Sensor Circuit Low Input
-P0302 Cylinder 2 Misfire Condition Detected
-P0507 Idle Control System RPM Higher Than Expected

I ran over to O'reillys too just to verify the codes but only got:
-P0171 System Too Lean (Bank 1)

I hope there is enough info for some help...

Has anyone ever heard of this? Any ideas?

It almost sounds like you have a leaky or cracked intake manifold, first step would be to replace your upper and lower intake manifold gaskets and see if that solves it IF it wont pass the carb cleaner test. A vacuum leak from a hose is almost always not temperature dependent since its always open, gaskets and manifolds though flex/warp/expand/contract when heating up and cooling down. Try again with the carb cleaner with a cold and hot engine and compare those results.

As MazdaTirol said this looks like a vacuum leak and the intake manifold gaskets are suspect. But before you pull out the wrenches simply push down on the manifold to hear if the hissing sound changes.
Check all other possible sources for vacuum leaks. Anything from hardened rubber hoses, cracked elbows and T connectors etc.
ScottyKilmer has Youtube showing how to use a cigar to find vacuum leaks. A mechanic's stethoscope could be helpful as well.

Thanks for the advice. Parts are here AND I've got the time to dig into this. I will let you know the results.

The link below to Luchboxx's post on the intake removal was invaluable. Thank you lunchboxx!!! He is right, the Haynes manual $u(k$ when it comes to the intake removal.

The PCV valve tube was the culprit. I changed the Intake gaskets while I had the intake off of course. Test driven and all is quiet. If I were able to see the PCV Valve tube before I started it may have saved a few hours. I think it is possible to get to it by taking the starter off instead.

FYI the dealer wanted $67 for the new tube, got it from AutoZone in 1 day for only $26 (O'Reillys also was able to get it for $26 but it would take 5-7 days). AutoZone did not have a listing for it under the Tribute. So I had to order it for a 2009 Ford Fusion (same part# 46034).

Thanks again MazdaTirol and TanProtege.





https://www.mazdaforum.com/forum/maz...al-2-3l-28483/

opps. here is the link to Lunchboxx's post :
http://www.mazdaforum.com/forum/mazd...val-2-3l-28483