Vacuum Tubing/3-way connectors/Valves
The vacuum tubing used everywhere wears down over time. It absorbs oil and doesn't hold as much air pressure as it used to. Example:
New (LEFT) vs Used (RIGHT) vacuum tubing
As you can easily see, the tubing on the right is twice as big, and it's oily, and spongy. Less effective!
I suggest you get a meter or two of this stuff and replace it where ever you can find it.
Places to replace it:
1. Engine, driver side, there is a lot of this stuff.
2. ALSO the same thing can happen to the three and four way splitters in the engine. If they look/feel ineffective, change them.
3. Under the front panel, under the ignition/steering/etc. Here you will find at least two at the ignition.
4. Doors have them too.
5. The HVAC system uses a few, two are under the noise encapsulation panels under your dash, in the center ish.
I spy one!
There is TWO of these:
And one of these:
Cake to replace.
Once you've troubleshooted this, or want to try something else, go back to the Dieseling Index
or try these: