squeek from engine
 

I have a '99 Boxster, and it sat for a year or so. I drove it after having the dealer tune it up and changethe oil. I washed it and now I have a belt-like squeek coming from the engine. I removed the back window carpet and engine cover. I had the car running, and sprayed belt dressing on the belt at the front that goes to the alternator. The sound continued andis coming from the back of the engine. To reach this area, I will have to drive the back up on ramps. Any ideas on the cause?

If it is a chirping that changes in frequency with engine rpm's, probably a loose spark plug. It's a fairly common issue.

P-wave nailed it.

They are pretty easy to get to, jack up the back of the car and remove the rear wheels, and the fender liner that is toward the front of the car.

Change Spark Plugs & Tubes

Pelican Technical Article: Replacing Boxster Spark Plugs and Coils - 986 / 987

I use this tool when doing spark plugs and it has been working great.

GearWrench 80546 5/8-Inch x 6-Inch Swivel Spark Plug Socket - Socket Set With Spark Plug Socket - Amazon.com

Steve

Does this only occur at idle or under deceleration by chance?

squeeking from engine
 

The squeek started when I wash washing it, and power washed the Passenger Side Air Vent for the engine behind the door. The squeek makes a constant noise. It gets quieter as the car runs. Sometimes at start up, the vacuum from the Pass. Side vent is very high and you can hear that vacuum motor. Only like 5 minutes. I wonder if I got something wet. Please give me any ideas you have.