I sure thought the fuel pump relay would be it

[jblackburn]

Correct. It sounds like it's confused as soon as it hits "closed loop" mode when the O2 sensor comes into play. This could be a MAF problem, could be an O2 sensor problem. Not sure.

[cn90]

For now, keep the code reader in the car, it will be very useful to diagnose issues.

[belyle]

One of my coworkers had a multimeter in his desk and I scrounged up a torx set so I could check the fuel pump coil resistance. 1 ohm, just like it should be. I'm debating driving over to a parts store to try to read the codes at lunch or just waiting for my wife this afternoon.

[belyle]

I got my code reader on and pulled the following codes:P0172
P0133
P1310
P0301
P0303
P0300

It's reporting O2 sensor is slow, car is burning rich and four misfire codes. I suspect the misfires codes are from me having to limp it to a parking spot this morning, but I'm not an expert.

I have a MAF sensor on the way. It will be in tomorrow. I will test the old one by unplugging it and driving around first. Could a bad MAF sensor really cause the shutoff symptom?

[erikv11]

P0172 and P0133 are front oxygen sensor codes. More often they show up because of a vacuum leak, but sometimes the problem is the O2 sensor itself. You are going to want to check very carefully for vacuum leaks How are the vac lines?

I agree with you about the misfire codes.

I wouldn't replace the MAF without testing it first. Expensive fix. But yes, it can definitely cause the shutoff symptom. The line around here is the MAF must be Bosch or Volvo brand, I stick to that, although recently a few people seem to have success with an aftermarket piece.

[belyle]

P0172 and P0133 are front oxygen sensor codes. More often they show up because of a vacuum leak, but sometimes the problem is the O2 sensor itself. You are going to want to check very carefully for vacuum leaks How are the vac lines?

I agree with you about the misfire codes.

I wouldn't replace the MAF without testing it first. Expensive fix. But yes, it can definitely cause the shutoff symptom. The line around here is the MAF must be Bosch or Volvo brand, I stick to that, although recently a few people seem to have success with an aftermarket piece.

The one I bought was from Amazon, a Bosch. It was $150 plus tax and overnight shipping. I am leaving town early Saturday morning and wanted to have my car fixed by then if I could. If I do my testing tomorrow morning and it's not the MAF, then I can return it. Amazon is pretty good about allowing returns. My local volvo dealer wanted $277+tax.

I also thought vacuum leak, and my lines definitely could stand to be replaced. However, I would think that a vacuum leak problem would cause poor performance overall and at any temperature, not just at higher engine temps. Plus, the problem with my car was very sudden onset. One day it was all hunky dory, the next it was dead on the side of the road. From what I've read, vacuum problems tend to sneak up gradually, although I guess that's probably not always the case.

[erikv11]

Sounds reasonable to me, regarding the vac lines. I confess I did not read over the whole thread ...

Post up how it goes. FYI It is fine to drive around town for 30 minutes or even a couple days (but not a road trip!) with the MAF unplugged, just don't jump on the throttle or anything.

[belyle]

Okay, I have done some more testing this morning. Note that it's about 35F out right now, so that might be mucking with my results.

I tried disconnecting the MAF (disconnect battery and drained system first). Car started fine and idled for about 15 seconds and shut off. It would start every single time, but would only run a short time. I thought it might be because the default map is no good for the cold air, but that's 100% speculation.

I plugged it back in and everything starts up and runs fine. I left the car running for about 20 minutes to get the temp up. Temp gauge read at the 1/2 way mark. Normal operating temp, basically. I tried disconnecting the MAF after the car was good and warm, and it behaved the exact same as before. Runs fine for 15 seconds or so and then shuts off. It doesn't sputter or anything, just from 800RPM to nothing.

I took the car out for a drive (MAF attached) and could not get any hesitation or stumbling at idle. However, at wide open throttle, I could get the power to complete cut out for a split-second and then hit again. I would take off from a stop, floor it and it would take off like a violated primate. Then after a second or two, the power would just die for a split second and then be back on. Car acted like nothing happened.

I checked the codes after I got back, and it had thrown a P0102, but that might have also been left over from when I had the MAF sensor disconnected. I think I cleared the codes, but I'm not 100% sure that I did.

So, I'm back to not knowing for sure what the problem is. I'm not sure if the engine should run without the MAF at this temperature, so I don't know if that test is valid right now. I have the new MAF coming today, so I could swap it in. But, I'd prefer to know for sure that's the problem before putting the part in and losing my ability to return it.

Any other suggestions/tests?

[jblackburn]

At WOT, these cars don't rely on the mass airflow sensor - they default to pre-stored WOT conditions in the ECU.

Curious though that it now behaves fine at partial throttle, which, as I understand, it wasn't before. Clean up the connector on your existing MAF sensor, get some MAF cleaner spray, and then fasten down the connector with a zip-tie to the top of the sensor.

[belyle]

Well, it was only misbehaving once everything was nice and warm, after driving for some time. This morning was quite cold, so like my testing earlier this week, I'm not sure the car got hot enough to bug out. So you think the blip at WOT is a separate issue, or still related to my other problems?