[wormser]

Recently had problems when starting my STS '08 V8. It rolls over 6 or 8 times before starting. After the car is warm, it doesn't seem to do it on restart. Also, sometimes during acceleration, the car will completely stall out (nose dive) but not die.

This seems similar to a problem I had on my old '02 Pontiac Grand Prix GT and replacing the Mass Air Flow Sensor did the trick. I know a Caddy is a bit more advanced so wanted to see if anyone had any insight.


Regular oil changes, replaced battery 2 years ago, replaced air filter and spark plugs last year. currently sitting at 115k.

Thanks!

 

[Frnkbooth]

Maybe fuel pressure? I would check it cold and then running. There is a fitting on the fuel rail. If you have no pressure when cold after overnight, something is letting it leak down.
Pump or injectors.

 

[wormser]

Fixed.

I used some cleaner on the Mass Air Flow sensor. It seemed to fix the hard start but still was stalling out during hard accelerations. I ended up replacing the Mass Air Flow Sensor with a new one. This just took a 7MM socket on a couple bolts. The part was $60 ($120 without the old one). Still didn't fix the problem.

I ended up replacing the fuel filter located on the passenger side underneath the car, just in front of the rear wheel. Getting to it was easy but removing was another story. This seamed to fix the problem. Note: the first start was a little shakey to to a loss of fuel in the lines during replacement.

Now when I accelerate and get to about 40MPH (where it use to stall out) the V8 really kicks in and starts accelerating much quicker. She's back to her old self. It was definitely getting starved for fuel under high demands due to the original fuel filter. Can't decide to bring back the sensor, but i know this was a problem on the old Pontiac so I might just keep the new one; they are all made in japan by the same company. The car is really running strong again.

4 years and I still love this car