Car stumbles, stalls and surges from stop

[Marccus]

Every once in awhile, sometimes once in two weeks, sometimes twice in a week, sometimes not for a month, the engine ('89) stumbles and chugs/bucks/backfires from first gear. eek!

Once I get going, it's fine and after I'm stopped and start again it's fine.

When this happens as I put my foot on the gas, I feel no power to the engine, it just stumbles and won't go anywhere, feeling like it will die. Then, I'll "mess" with it, hitting the gas randomly and shifting from second to first and it seems to "wake up" and get going. shrug

I recently changed the fuel filter, thinking this could be the problem.

Also within the last several months, cleaned and rebuilt intake manifold, throttle body, new plugs and wires, flushed coolant system, new coolant lines, new radiator.

I add one bottle of Redline Fuel Injector additive to my tank about every month.

I've never changed the fuel pump or have had the injectors cleaned since about 60K miles (currently 260K miles).

Could it be the fuel pump?

 

[projectSHO89]

Try disconnecting the Cam Sensor.

The car will start (will probably take several attempts) and run fine without it. You will loose the Tachometer.

The cam sensor has been known frequently to cause hesitation/bucking/stumbling.

Might be the crank sensor on its way out.

It's also possible that it is the fuel pump. You would have to have a fuel pressure guage hooked up while the engine falters to know for sure.

Steve

 

[pjtoledo]

Another possibility is the alternator. I had the infamous low speed stall on my 87 Slo wagon. Turns out the alternator put out so much ripple that the PCM and ignition was not able to function properly. Only happened at low RPMs, above 1200 it would run ok for hundreds of miles.

Perry Toledo,Ohio

 

[Marccus]

Thanks to both, projectSHO89 and pjtoldedo. I need to replace he cam sensor as it is covered with oil from the cam seal leaking, which I will replace at the same time.

I'll check out the crank sensor if that doesn't do it and then finally replace the fuel pump as a last resort.