Engine stalling, cutting out, surging

[scorpiowoman1025]

I posted an earlier problem about my 1995 Olds Cutlass Supreme with a 3.1 liter V6 engine. The car has about 185000 miles on it. I realized it needed some maintenance done so we did a fuel cleaner, oil change and replaced the pcv valve and plugs and wires. It ran great for about a day or so and now it is stumbling on the freeway and also stalling out completely at stop signs, almost like it isn't getting fuel or something. I have also replace the fuel system including fuel pump, twice, fuel filters twice and fuel pressure regulator. All in the last couple of months. I also during the last few days have done the oxygen sensor, map sensor and again checked the plugs and wires. We also put in a new air filter. It seems to be getting much worse and I am not sure what is completely causing it. It is not giving us anything in the way of codes and a recent trip to the shop was not able to solve the problem. My mechanics are kind of stumped and so is the repair shop, any ideas about what to do next?? I can't afford to continually having to worry whether I will make it to work or home

[Tech II]

Can you easily recreate the problem? If yes, then time for a new mechanic....

[scorpiowoman1025]

Obviously if I could one of the two shops and mechanics would have been able to figure it out. It doesn't always do it or on a regular basis and there are no codes. However we did replace the plug wires because one had a defect in it and the throttle position sensor and the battery. It is quite a bit better but still a little surging, no more stalling though and it starts right up.

[Cammy_01]

My friend just stalled out coming up my driveway.. from the surging at speeds and at idle and stalling my first step was to check fuel pressure. Key on only, 30 PSI exactly when fuel pump hums for a second, then when I release the fuel pressure with the gauge, key still on, it drops to zero, but some fuel still trickles out the release on the gauge continuously with no hum from the fuel pump, but amazingly it still sometimes runs. Maybe someone can chime in, but my question is a bad fuel pump or does the computer control voltage to the fuel pump. Everytime the key is turned on it hums and goes to 30 psi, but did not 2 times out of 20 times we tested it.. also turning key on and at 30 psi then key off it does hold pressure so I assume holding pressure means the fuel pressure regulator is good.

My suggestion to the originator of this post is have that fuel pressure checked or buy a $35 dollar fuel pressure gauge at Autozone and check it yourself.

My friends car is also a 95 3.1 v6 and your symptoms sound very simular and possibly the same issue.

[scorpiowoman1025]

I appreciate that, it was one of the first things we checked but fuel pressure and pump are working fine. I am leaning more towards the egr valve now. We have also replaced the tps sensor, battery and wires again, one was fried and it made a huge difference in the last couple of days. It is running almost 90% better, still a small hesitation now and then but doesn't stall and gas mileage is better!! Good luck hope you get yours fixed soon