22R engine will not idle after warming up and then stalls and shuts while driving

Okay, I took matters into my own hands since local mechanics charge a fortune and only make matters worse. The engine still does not want to idle and dies when driving or coming to a stop. The gas pedal has to be feathered to keep it running, which is not easy with standard transmission.

The last mechanic plugged loose vacuum lines instead of fixing them. So, I have no idea what he did. I do not trust him, and he is not one to talk to because he seems to get defensive.

Previously, I had identified three plugged vacuum lines (see attached picture) and according to our conversation, I tried all possible combinations of connecting the vacuum lines and this is what happened:

A > Connecting 1 to 3 with 2 plugged - High idle.
B > Connecting 1 to 2 with 3 plugged - No change.
C > Connecting 2 to 3 with 1 plugged - Runs a bit better with low idle, but "choke opener" remains plugged.
D> Connecting 1 to 3 with a tee connecting 2 - Runs the best but dies more due to low idle.

Out of these choices above, I feel best with "D" because the choke opener" is connected in this arrangement. Coincidentally there are two other vacuum connections with a tee in this setup like the diagram. (I can't tell what the connections go to).

Now, with the fuel/air mixtures and the cold and hot idles all adjusted at the Toyota Dealership I really do not want to touch mess with them yet. If my last and final diagnosis concerning the catalytic converter fails, then I will adjust the warm idle up with the current "D" setup.

NEW CONCERN TO THIS: I have a friend who had the same exact problem with his vehicle, after doing everything under the sun, it turned out to be his catalytic converter causing the problem even though the diagnosis did not identify it. He removed the catalytic converter, and the problem went away. I have read something similar in the Toyota forums

So, what happens with the O2 sensor when I replace the converter with a straight pipe? (There are no inspection stickers required in my state).

If this converter fix doesn't work, I will then idle up the warm idle and then I am done.

I forgot one major detail concerning the catalytic converter and exhaust system. I previously had the muffler replaced. As it is now, the exhaust runs extremely hot. I have never felt exhaust on any vehicle as hot as this is. It will actually burn your hand. I do not know if this means anything, but it's not normal.

Back up to the message above my catalytic converter comment for details concerning the vacuum hose work I did. I forgot to add the catalytic converter / hot exhaust info in the vacuum hose comment and wanted to add it in case it meant something. Sorry about that.

Again, I ask, what happens with the O2 sensor when I replace the catalytic converter with a straight pipe? Does not having the sensor connected cause problems? (There are no inspection stickers required in my state).

Thanks again.

Well, I assume you read my vacuum line info above but didn't comment on it. I am sad to say that the current vacuum "D" arrangement I decided to go with is not working out at all.

Today, I drove 60 miles and used almost half of a tank of gas and the engine continued to die as usual. My gas mileage went from 30+MPG to about half or less. So, I guess plugging all three vacuum lines as they were before is my only choice left. I am stuck with that because every mechanic I try makes matters worse.

I will attempt a final try at replacing the catalytic converter, hoping that will do it. What a nightmare this has been and still is.

Here is a repost of my vacuum situation:

Okay, I took matters into my own hands since local mechanics charge a fortune and only make matters worse. The engine still does not want to idle and dies when driving or coming to a stop. The gas pedal has to be feathered to keep it running, which is not easy with standard transmission.

The last mechanic plugged loose vacuum lines instead of fixing them. So, I have no idea what he did. I do not trust him, and he is not one to talk to because he seems to get defensive.

Previously, I had identified three plugged vacuum lines (see attached picture) and according to our conversation, I tried all possible combinations of connecting the vacuum lines and this is what happened:

A > Connecting 1 to 3 with 2 plugged - High idle.
B > Connecting 1 to 2 with 3 plugged - No change.
C > Connecting 2 to 3 with 1 plugged - Runs a bit better with low idle, but "choke opener" remains plugged.
D> Connecting 1 to 3 with a tee connecting 2 - Runs the best but dies more due to low idle.

Out of these choices above, I feel best with "D" because the choke opener" is connected in this arrangement. Coincidentally there are two other vacuum connections with a tee in this setup like the diagram. (I can't tell what the connections go to).

Now, with the fuel/air mixtures and the cold and hot idles all adjusted at the Toyota Dealership I really do not want to touch mess with them yet. If my last and final diagnosis concerning the catalytic converter fails, then I will adjust the warm idle up with the current "D" setup.

I have discovered that this "D" vacuum arrangement has severely cut my gas mileage down about 66%. A 60-mile round trip used almost half of a tank of gas. Before, it would barely use a quarter of a tank. So I am at a loss for what to do now. :(

Thank you so much. You are my only hope. The 3 mechanics I have used, including the Toyota Dealership, could not fix this. :)

I doubt the choke was open, the engine was warm when I was doing the vacuum line changes. I did not have a tachometer, but the engine RPM's were dangerously high.

It has federal emissions. Thank you again. :)

If you look to the right of plug 2 (pictured below), you will see a header of small vacuum metal tubes that go around the engine attaching to other components. I will try to trace that tube and see where it goes and snap a picture of what it attaches to. So, number 2 is not the BVSV.

So, if I am understanding right, I am to connect 1 to 3 with the other vacuum line going to the BVSV instead of where it is connected, which is to 2.

I will see what I can do tomorrow and get back to you on this. My friend, you have worked hard on trying to help me and I sincerely appreciate it. :)

So sorry about the late response. Trying to figure out these vacuum lines is a mess. The red arrows point to a header of 1/8" tubing that splits up and goes in many directions to different components with some ends also plugged.

This tubing is hard to see, follow and trace in some areas to exactly where each tube goes and to what component, so I cannot identify the component name

I cannot see how anyone can possibly see what they are doing or figure this out as some of the areas are so tight to try to get in to.

I suppose it is time to say thank you and give up. Take care.