Hello, I'm new to this forum. We bought my 2006 Volvo s40 2.4i back in March. At first there was no issues and only a few things needed fixing (small issues, oil change, etc). A few months after this, the check engine light came on, and then I began having real issues. The car would have issues accelerating. Getting on the highway and accelerating would cause the car to almost feel as if there was a hesitation or a gust of wind pushing against the car. The code that registered on OBD was the MAF sensor. We replaced this and the issue was still there. Then we replaced the fuel rail pressure sensor, as well as changed oil, and even added a missing bolt that couldve been breaking the seal on the intake manifold. This seemed to fix the issue and the check engine light went off. Everything ran like brand new. Then, about a week later, when accelerating to get on the highway, the check engine light came back on. Over the next two weeks it would come on and go off at random. The car still ran fine with a stall about every two weeks. Now I stall every single time I come to a stop light , stop sign, or a stop in general. The RPMs sometimes drop and the car recovers by giving itself gas, but other times it just dies. The car also has a very rough idle, and if i come to a stop and it doesn't die, the RPMs fluctuate up and down. I should mention that the car has 116,033 miles on it. Any help would be greatly appreciated.

 

Have you checked fuel pressure? The fuel pressure is regulated by voltage to the pump through the fuel rail pressure sensor. Did you buy a genuine Volvo fuel pressure sensor? I ask because I have had more than one aftermarket part give me grief with my Volvos. The latest was a coolant temp sensor, brand new out of the box, that was defective. A genuine Volvo part fixed my problem. Don't trust that because it's new, it's good. Always test.

 

We have only put genuine OEM volvo parts into the car. The FPS is an OEM part. When reading the fuel pressure with an OBD2 reader it hovered around 55psi. Never got too low or too high. On another forum someone has stated that at this point,m after we have ran through a lot (on that forum) it is more than likely a vacuum leak after the MAF.

 

IM HAVING THE EXACT PROBLEM.
Have you figured out the problem?

 

You are best to create your own thread, list your symptoms, any DTCs, attempted fixes and other info. Year make model etc.

Issue's like this can be a lot of different things. This particular post seems like an intake leak after the MAF and even VIDA will give you a heads up on a where to start if the car is scanned with that.

 

transmission position sensor. My battery acid corroded these sensor wires located right underneath the battery. One sensor on top of transmission and the other on side behind the wheel weld shield. Had this issue a few years ago. Exact same symptoms.