1993 Volvo 850glt mystery woes!

Don't get me wrong, this car has been great to me! bought it a year
ago with only 95k miles on it, but right away a problem started. If i
filled the gas tank more than halfway, the car started to seriously
hesitate when accellerating, sometimes even stalling out completely.
Being the impulsive and poor young college student that i am, i fixed
the problem by never filling the tank more than halfway.

Well, problem's gotten worse (imagine that!) The car more or less
hesitates all the time now, especially badly under 3k rpm. The car
also stalls out intermittently, and seemingly randomly. Suddenly the
throttle will just stop responding, and the engine will slowly wind
down until it stalls out. Sometimes i can just put it in neutral (at
which point it'll stall out right away) and after about 20-30 second
of coasting pop the clutch and it'll start right up, but most of the
time it starts back up with the same problem. I have to pull over,
wait 2-3 minutes, and it starts right back up again.

Yet, throughout all this, it doesn't give up a single error code.
I've replaced the fuel filter, and i added fuel injector cleaner, my
next bet is probably going to be to change the fuel pump and hope for
the best. Any ideas?

 

There are some relay issues with the fuel system on 850's. Check the
Brick Board. I thought my 94 was dead, turned out to be bad spark plug
wires, shorted out , but kicked out knock sensor codes. I could see the
shorting in the dark. In Texas, I could not get a 93 850 with standard
transmission. Where are you?

 

One thing I would check is the prepump in the gas tank. There might be a
short rubber connecting hose from the pickup to the pump which has
deteriorated and this might be the crux of your problem. I had a 78 wagon
with this same symptom and found that the hose inside the tank was shot.
Changed it out for a few cents and my volvo was as good as new. Give it a try!
Good luck!

 

I also had a 240 where this small rubber hose has slid off. It would
pump gas if the tank was full enough or when going down hill, but would
suck air when I climbed hills. The mechanic know immediately what it
was.