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Followup To
Question -
1996 Pontiac Sunfire, 2.2 liter 4 cylinder.
I start the car, put it in gear and accelerate steadily.
After about ten seconds it falters for three or four seconds, then it runs fine.
It will do this every time you turn off the ignition and restart the car.
The tach drops to zero when it falters, but the speedometer continues to read properly.
No warning lights appear.
It feels like something is momentarily interrupting the fuel.
I can start the car and rev the motor in park, it will never falter.
I can start the car, hold the brake so the car won't move, put it in gear, rev the motor, it will not falter until I release the brake and the car begins to move.
Once it happens, it runs fine until I turn off the ignition, and restart the car.
Answer -
What mechanical work or ANY kind of work has been performed on the vehicle recently ?. As most problems that occur after a recent repair was made can be traced back to the area of where the repair was made.
Without actually having the vehicle to experience this fault, I would suspect an intermittent fault in the TS sensor (Throttle Position Sensor). You may test it and it may test fine but it only takes a small intermittent fault to stumble the engine.
My next concern would be an intermittent fault in the CRANKSHAFT SENSOR.
If it were fuel related, I would expect to see a momentary drop in engine speed.
Most intermittent faults will NOT illuminate the CHECK ENGINE or SERVICE ENGINE light on the dash.
A notorious re-occurring problem is the normal blackish sticky residue that builds up around the edge of the throttle plate area of which can be cleaned by numerous spray can products available at any auto parts stores.
autohelp
What does it mean that it only happens once after starting, and it happens every time? By the way, there is a momentary drop in engine speed.
Thanks for the help.
Mike
AnswerHappening ONCE after starting would be an INTERMITTENT fault.
If it happens everytime, the check engine light will usually set a code and NOT illuminate. Hvae someone access the vehicles computer and see if there are any intermittent codes set.
autohelp
