1998 Buick Regal - P0300 code - stalls

[pacem]

P0300 code

Buick Regal 1998, 185,000 miles, automatic

The vehicle loses power at full throttle, usually going up a steep hill and cuts off. It does not seem to cut off in any instance, although sometimes I get hesitation when hitting the gas, and then it goes away. I pulled the codes and got P0300.

Quote:

A P0300 diagnostic code indicates a random or multiple misfire. If the last digit is a number other than zero, it corresponds to the cylinder number that is misfiring. A P0302 code, for example, would tell you cylinder number two is misfiring. Unfortunately, a P0300 doesn't tell you specifically which cylinder(s) is/are mis-firing, nor why.


In addition to that, it can be hard to start immediately after it was turned off. Waiting a while seems to help and also hitting the gas pedal seems to help. I don't know if it's a part of the same problem or some other problem but it does not seem related to either starter or battery because both are 2 years old.

I cannot narrow it down to a fuel or an ignition problem.
A quick search suggests it could be a MAF sensor, or Crankshaft Position Sensor, or injectors, among other stuff.

 

[michaelluscher]

Crank sensors common
Fuel pressure holding steady? Pressure regulator not leaking?

 

[bullwinkle]

Might try a nice run of Techron, with a Top Tier fuel such as Shell V-Power-fixed a nagging, annoying miss on my company van.

 

[Drew99GT]

You can easily diagnose the MAF sensor by unplugging it and running the car; if the symptoms disappear, the sensor is bad.

 

[John_Conrad]

fuel pump, if you have to cycle the key a couple times to build pressure.

i had these exact symptoms on my very similar 97 olds 88.
including the cutting off trying to climb hills and the hard to start thingy.

 

[ls1mike]

Fuel pump, it is time at the mileage.

 

[pacem]

Originally Posted By: ls1mike
Fuel pump, it is time at the mileage.


sounds plausible.

 

[pacem]

http://www.ebay.com/gds/5-Common-Symptoms-of-a-Malfunctioning-Fuel-Pump-/10000000177634796/g.html

2. Vehicle Loses Power While Accelerating
The feelings generated by this second symptom are very similar to the first. However, rather than experience a sputtering sensation while driving, vehicles will experience it upon acceleration from a stop. Generally, the vehicle will initially move before making noises and jerking around as if it will stall. Then, it will continue on its acceleration path smoothly.

What This Means
The process of acceleration creates an increased demand for fuel by the engine. A malfunctioning fuel pump, again, cannot maintain the required pressure to deliver this fuel in a steady manner, thereby causing the engine to improperly mix fuel and air and lose power. Once pressure is restored, the engine is able to run smoothly and the car takes off.

3. Sudden Loss of Power When the Vehicle Is Under Stress
A car or truck is put under stress when the work needed to complete an ordinary task, such as forward movement, is somehow hindered by external forces. Generally, this occurs when climbing a hill or when hauling a load. If, when completing these tasks, the vehicle loses power, cannot accelerate, or begins to sputter, the fuel pump is a possible culprit.

What This Means
Generally, a fuel pump, even an aging one, can maintain a steady stream of fuel and pressure when operating under normal conditions. However, once put under stress, the weakening elements of the pump will begin to take control and the fuel delivery will not be able to keep up with its demands, leading to power loss.