Hopefully this is where I need to post this. I tried to start my 1995 850 GLT earlier and it immediately died. After that, I could not get it started. It was cranking but just didn't seem to be getting any pressure. Once I finally got it to start, it idled very rough and kept stalling. After a few more attempts, I got it running and gave it some healthy accelerator, getting the rpm to about 2800. After that it seems to run fine again. What could have caused this? I also just pulled a P0172 OBD-II code from it. I think this is a vacuum leak issue, and could this be the cause for the rough start? Lastly, anyone that has a good description of which vacuum hoses I should start with, I would appreciate your help. I have tested the MAF and it is in working order, so where do I go from there?

 

Kinda doubt just a vacuum leak if the problem started occurring pretty suddenly. Also would probably run lean, not rich. If the O2 sensor is accurate (and this is another possible issue, old and slow O2 sensor, but doubtful would cause rough startup) then the car is not burning all the fuel it is getting, for whatever reason.

I would check to see that the fuel pressure regulator is not bad and leaking fuel through its vacuum hose. This would cause flooding and difficult starting, as well as causing the rich DTC. Pull your spark plugs and see what they look like also, how long since the car has had a regular tune up?

 

The spark plugs look good, less typical wear. I completed a full tune up about three months ago. This issue happened about a year and a half ago too, but after a little bit of driving it went away. It was running great before this happened and now it is back to running great. Thank you for the tip about the fuel pressure regulator, I will check that and make sure it is not leaking. Hate to even think about letting someone work on it when the problem isn't present. That, and in NW AR the closest person who works on volvos is a three hour drive.

 

fuel filter?

 

It very well could be the fuel filter. That would explain the sputtering after starting. Would it cause the error code or am I dealing with two separate issues here?