Car stalling while driving?

NEWTOOLDS

MEMBER
1996 OLDSMOBILE CIERA
3.1L
V6
2WD
AUTOMATIC
65,400 MILES

I have an inherited the car listed above, I have been restoring. Driven down from Washington to Nevada without issue. Sometime after arriving in Nevada, I began experiencing intermittent stalling of the vehicle while driving. No check engine light came on. The car would run perfectly in the morning. Then after work (in warmer weather) on the commute home roughly 20 miles of freeway driving the car would stall at freeway speed or on city streets.

I eventually got trouble code P0171, O have subsequently changed Plugs and Wires, bank 1 and 2 O2 sensors, air and fuel filters, and the fuel pressure regulator. Now the car starts and runs fine for short periods but will stall about every 3-5 miles and restart and run after about 30-60 seconds. Then repeats cycle. I was thinking perhaps Fuel Pump? Honestly at a loss. I have no check engine lights or trouble codes.

1 Reply

JACOBANDNICKOLAS

MECHANIC
108,355 POSTS

Hi,

The code indicates a lean fuel mixture. In most cases, this is the result of either an engine vacuum leak or a failing fuel pump.

Start by checking for leaks. Here is a link that explains how to test for engine vacuum leaks and how to repair them. Keep in mind, the 3.1L engines are known for intake gasket issues, so check that area carefully.

https://www.2carpros.com/articles/how-to-use-an-engine-vacuum-gauge

If there are no leaks, check the fuel pump pressure. Here is a link that explains how it's done. You will need a fuel pressure gauge, but most parts stores will lend one to you.

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

If you look at the pic below, it provides the manufacturer's fuel pressure specifications.

Let me know what you find.

Joe

See pic below.

Image (Click to make bigger)