Hello all,

For context, I am not mechanically inclined, I am a 35-year-old disabled woman who happens to love these cars and have not run into a problem this long lasting until now. I’m very interested in learning about my car and am passionate about learning and wish I could do the tests I have on my list it needs and it’s tough finding a mechanic who can or will work on my car. My dad knows a little but he is not confident about hotwiring things to test them separately for example, so we’re a little limited on our own. My friend who is a mobile mechanic is going to be taking this car at some point but he’s being flaky right now so I’m trying to troubleshoot with my dad in the meantime.

I have a 1993 Volvo 240 that has had a problem for three months now ever since the ambient temperature reached below 50°F. On the first start of the day, it cranks and starts and within 30 seconds, after heaving and a rough idle, it stalls. If I open the throttle, instead of letting it die, it’ll even out and run fine for the rest of the day, except for the fact that it’s running rich.

It threw the code 2-3-1.

Three shops in three months have given up on the car. So far we have checked the fuel pressure regulator, the mass airflow sensor works, the O2 sensor works, fuel pumps both engage and I hear the fuel pump relay turn on in position 2. We reviewed the hoses for vacuum leaks, replaced hoses that had leaks, and still no change.

The previous shop it was at changed the coolant temp sensor (Bosch), and still no change in performance. So I was wondering if anyone else had any other ideas besides what I would like checked next, which is:

1. Check the idle air control valve.
2. Check coolant temp sensor resistance at the ECU plug when it’s hot and cold to make sure it’s getting the right readings in case there’s an issue with the wiring.
3. Check the airbox filter housing flap valve thermostat. (The MAF is fine and I’ve been driving it so I feel like I would have fried it by now so maybe it’s not this.)
4. Check electrical grounds at the ECU and any other wiring.
5. Clean the throttle body. It does click with manual movement when the car is off, so the throttle position sensor is working.

Tonight my dad and I looked for a cold start injector but I don’t believe the 1993 240 has a cold start injector. We were told to look under the inlet manifold and we couldn’t find one and there are only four fuel injectors together to count.

Thanks for reading if I’ve left out anything important, let me know. In the last week the temperature is dropped from the 40s into the low 30s Fahrenheit and it’s been doing the same thing every day since the first truly cold day of autumn in November when it dropped below 50 degrees Fahrenheit.

I don’t know if I’m making this more complicated than it has to be but the fact that three shops have given up on it is making me feel disheartened and frustrated.