Breadboard inconsistencies

I am working (unfortunately) down to the wire with a sensor program using a HC-SR04 sonar proximity detector. I get the sensor to work fine, then I try to add a sensor and the second sensor doesn't work. I have tried to trouble shoot as much as I can, and its not the sensor because I have tried all of my sensors and they all work when I connect them to this single connection. The sensor works fine when I plug it directly into the arduino board, but when I move over to the breadboard, sometimes it works on some horizontal lanes, sometimes it doesn't. Have i damaged the breadboard? How would I be able to tell? Any insight would be awesome, as I am new to the world of arduino and electronics in general.

Cheap breadboard and cheap jumpers most likely. try jumpers with bigger pins (the square ones) or solder onto a proto-board.

Honest question: Do non-cheap breadboards even exist?
I'm having a similar problem as the OP, and I really don't want to break out the soldering iron every time I need to change something.

Some people would advocate that there are high quality bread boards but I have never come across one.

I have what I consider a "cheap" breadboard, and I won't use it. The pins are so tight in it you need a little crowbar to remove 8 pin dips.

Show us the breadboard cct image that is not working.

I have never experienced a problem with one of these, over 40 years.
Back then they were called SK10 boards.

No more than a header pin size (.65mm) in any hole, only I.C.s in the middle of the board.

Use a staple remover or small bladed screw driver to free I.C.s

Never had problems myself. I always connect a 47uF and 100nF cap across the power rails for starts, then make use of them liberally. Make sure to avoid ground loops.

Check if you have a split rail board ... may need to add some jumpers.