Hi:

I've noticed a whistling noise on moderate to heavy acceleration with my car in recent weeks. The overall performance is fine and it does not lack power. Was thinking it was maybe a vacuum line or leak of some sort.

Any suggestions on how to slay the dragon?

Thanks.

I'd have to hear it.

Have you done any mods, like a gutted air box? If you're getting a strong whistle, but aren't having any operating problems, it'* likely in a secondary system. If it was in the upper or lower manifold, both the MAF and MAP would be getting fooled and you'd have operating problems. It were a leak in a seating on the throttle body only the MAF would get fooled and the PCM could still come close with fuel trims. Generally speaking the main problem with vacuum leaks is that you usually CAN'T hear them.

A historic and prevalent "whistler" has always been the PCV valve. I'd pop that out and make sure the two rubber O-rings are intact. Shake it to make sure it rattles so you know it'* a free valve. If there is any question, replace it for some light bucks.

Just make sure those o-rings are OK and in their proper places.

If the PCV valve is OK, then spray carb cleaner around the vacuum lines, also around the EGR, and fuel injectors. If the RPM changes, you have a vacuum leak.

Having whistled in the past. I'm on the "check the pcv" kick.

My car doesn't have any mods. I replaced the PCV within the last six months, along wth new plugs and wires. Like I stated earlier, the performance is fine and I get almost 27 MPG on the highway.The perfomance does not suffer one bit....just a light whistle on moderate to hard acceleration usually during a merge into traffic. I will re-check the PCV and then spray the carb cleaner as suggested to see if the idle changes any. Thanks for the input!

I would check around the gaskets on the throttle body and around the UIM. Higher vacuum under load.

I remember certain Bonnes exhibiting this whistle noise on moderate accell at certain throttle positions. GM released an updated throttle body to correct this. The whisitling throttle bodies caused no other problems, only the whistling noise.

install new PCV + whistling noise = check PCV O rings

Pcv sounds logical, however I would first check with a Dealer and have them run a bulletin search(or Alldata, etc.) to see if your vehicle was involved in the updated throttle body bulletin. If memory serves me correct, it was 98'*, but only within certain V.I.N. breakpoints. This could save you alot of time trying to chase down something you would otherwise never find.