'96 850 GLT Surging

[bensr20det]

How many temp sensors are there? I am willing to replace anything at this point. I am reading that the ECT sensor is like a fan switch. Will it change the air/fuel mix also?

[j_cd]

I don't know exactly. Looking at parts geek right now, they carry an evaporation pressure sensor that is part of the fuel delivery system. You could also try a different Throttle Position Sensor. They're easy to find (on junked Volvos) at parts yards. I didn't suggest this before because I didn't think TPS was part of the fuel system, but it is. Bad TPS can definitely cause surging. It's a fairly easy part to replace, on the throttle body.

[bensr20det]

I replaced the throttle position sensor today. I unhooked the battery for a while and hooked it back up. After driving for about 5 minutes it began surging again at a stop sign. By the time I got home it had stopped. Any other ideas please I am going nuts trying to pin down the cause. Whatever it is won't just break so I can find it, by the time I look at it it stops acting up. Please help.

[j_cd]

Well that's a drag. Is there a mechanic shop around there that specializes in Volvos or Euro cars? It might be time to hook your car up to a computer and see what it's doing. You might call around for a computer diagnosis estimate.

[bensr20det]

Yeah there are a few places around town that specialize in Volvos I just figured I could track it down. Are we out of things to look at and I need to give in?

[j_cd]

I don't know what else to suggest. Someone more advanced might be able to help you track it down. Otherwise, maybe just pay for the diagnosis, then fix it yourself.

[bensr20det]

OK so I have more info for anyone willing to help me. So after replacing the TPS I decided to go drive until something broke so I could replace it. I drove about 50 miles until finally it started acting up. Once it did I drove directly to my friends house and he has a very nice snap-on scanner. Once I got to his house the check engine light finally came on. The code was a p0103. Which lead us to believe it was the mass air flow sensor. So I went to auto zone and bought a remanufactured one and installed it in the parking lot. Well that was a no go as well. The problem seems to be even worse at this point. I have a video I made and I am uploading it to YouTube now. As soon as it is up I will share the link. Any ideas why this P0103 code would show up would be a great help. Once again thanks for any input you may have for me.

[jblackburn]

I can tell you that the parts store sensors almost NEVER work - in fact, almost make problems worse. You'd be better off junkyard hunting for an OEM mass airflow sensor.

Does the air hose to the throttle body have a hole in it? Any huge vacuum leaks anywhere?

[j_cd]

jblackburn speaks the truth. Anything but a Bosch MAF will not work. It's one of those weird things about these cars.

[bensr20det]

The sensor is a Bosch. Isn't that OEM? The flexible pipe from the MAF to the throttle body is in great shape. The last one was indeed full of holes but I replaced it about a year ago. The hoses from the intake to and from the IAC are not super tight but pushing them on tighter makes no difference.