Hi all,
I've been lamenting ceaselessly about a vacuum leak but have been unable to clearly identify where it is. I believe I am getting closer based on observations from driving with the radio off and all the windows rolled up so I'm calling on you all again.
I know there's a metal vacuum can in the engine compartment but is there also a vacuum can of sorts in the cabin? If so, is it connected to the accellerator?
Here are my observations (please forgive the mixed syntax as a vacuum is an absence of matter and I treat it like it's the opposite):
- When I step on the accellerator I can hear a short hiss as vacuum builds up. [This indicates to me that the vacuum bottle is "empty" and is being "filled" with vacuum.]
- When I coast and brake I cannot hear any vacuum hiss, but when I again step on the accellerator after a stop I hear the brief hiss again. [This indicates to me that the rate of vacuum "leaking out" is slow but constant.]
- When I step gently on the accellerator I can keep the hiss constant. ie. [rate of vacuum applied = rate of vacuum loss.]
- If I release the accellerator before vacuum has built up (eg. part way through step 3) the car will do one of two things: 4a) Stall. 4b) All the dummy lights will flash, the engine will falter but then recover and idle normally. This is a near-stall with RPMs dropping to just above zero and then recovering.
This problem is most evident in stop-and-go traffic or where gentle accelleration is the norm. When I stomp the gas there's rarely a problem (although sometimes RPMs take a short, sharp dive before climbing normally).
There are probably a dozen feet of hoses that could be failing in this scenario but, since I can hear it so clearly, I have to assume that it's happening inside the cabin so I'll start with what's in there.
Any suggestions on where I should start checking first? It's a pretty awkward place to work as I have trouble jamming my portly torax under the wheel to see what's going on.
Suggestions are, as always, very much appreciated.
blurp ps. I believe (hope) that resolving this will address my cold-start/warm-start issues, my cruise control problem, and my rough idling problem all in one shot. If not then hopefully it will get me closer to a complete solution!