Acts like it's running out of gas or fuel pump failing

hiroshima1320 · Post by **hiroshima1320** » 19 Mar 2017, 19:50

I have a strange intermittent problem. As I'm driving the car will drop rpm, acting like it's running out of gas or the fuel pump isn't running. It won't stall right away, or necessarily every time, but it will sometimes. If I pop into neutral, soetimes it won't rev to more than 3000 rpm or so. Sometimes it just straightens out and will run fine for a while. If it stalls I'll have to cycle the key a couple times then it will run fine for a while. I don't think this is an ETM problem, the symptoms aren't the same. I changed the engine shortly after I bought the car, it has a rod or 2 through the side of the block after a low oil pressure situation. I changed everything pcv, cleaned the throttle body, and that was about 15k ago, with no other major problems. The fuel pump was also changed about 5 months ago. I'll try to pull codes tomorrow.

Post by **abscate** » 23 Mar 2017, 04:57

The best way to diagnose fuel delivery problems is to monitor the fuel pressure at the rail. A good system will take several seconds to release pressure at the "tire valve"

A fuel gauge is the correct tool to definitively diagnose or you can sacrifice a cheap pencil type gauge too.

I think your 2002 Turbo got the Bosch throttle body instead of the sexy Italian one, so you get the reliability but no panache.

mwhittie · Post by **mwhittie** » 23 Mar 2017, 05:21

I had a similar problem on my 97 850 awhile ago and found a strange problem that fixed it for good. Upon inspection of the fuel pump after removal, I found the supply hose had "shrunk" a bit separating it from the lower pick up area of the pump frame. This caused about an 1/16" gap allowing only some fuel to get into the delivery. I repositioned the hose for full engagement and that did the trick. You will have to get the seals necessary to remove and replace the fuel pump or you will risk having leaks.

Post by **oragex** » 23 Mar 2017, 06:18

I'd also put on the check list the charging system starting with the alternator, power cables, and finally the battery and it's connectors

Post by **chrism** » 23 Mar 2017, 15:10

We had fuel pressure sensors fail on both our 03 NA and 05 turbo. The 03 threw a check engine light immediately. The 05 stumbled and stuttered intermittently for weeks before it finally threw a CEL. As mentioned, monitoring the fuel pressure with a test gauge showed that the engine stumbled in sync with a drop in pressure.

goldxc70 · Post by **goldxc70** » 28 Mar 2017, 14:47

I'm having a very similar problem with my 2004 XC70. What I have discovered is that it only happens when the tank is less than 1/4 full and the engine is hot. Mechanic has suggested changing out the fuel pump but isn't certain that is the problem. He also changed a fuel pump relay but that didn't help.

First time it happened, I was on a highway and each time I pulled over, I was able to immediately restart. After this happened 2 or 3 times, the car wouldn't restart leaving me stranded on the road side. Anyway, I had my 4-way flashers on for a couple of hours and I noticed them fading, interior lights dimming in time with flashers etc. and figured I might just be having battery issues. Given that the battery was original, I replaced it next day but that didn't fix the cutting out issue.