My 1990 240 has a pretty bad gas smell when I’m driving with the windows down. I’ve checked the injectors for leaks, I can’t seem to find anything. Any help would be great

 

Many other sources of gas leaks... I'd raise the car and look at the lines, filter, etc. going back to the tank--shouldn't be too hard to find.

 

Is the smell more pungent when looking under the hood? If you're sure it's a gas smell and not exhaust fumes make sure to check all your fuel lines, a loose fitting or failing hose could be leaking fuel maybe it is evaporating before you catch it. A little gas goes a long way as far as smell.

 

Don't know where you live but if you live in the rust belt there are a couple of places where I ran into problems:

1) Banjo bolt that attaches the fuel line to the fuel filter. Rust takes these over time and can produce pinhole leaks here as the fuel is under high pressure (~45 PSI)
2) Return fuel line. There is a return fuel line that goes from the fuel rail back to the tank and is made of steel. This can rust and start to leak.
3) Fuel filler tube that runs from the filler port to the tank. This can develop pinhole leaks where it attaches to the tank due to the clamp there being steel while the filler tube is aluminum.

1 & 3 will be fuel smell near the rear of the car where 2 can be anyplace from engine to the fuel tank.

 

I have a 1992 240 wagon and had a similar mysterious smell. I found a pinhole in the banjo bolt. Number 1 in the above post.