Car has 165,000 miles. Engine (3.8 liter) never replaced or rebuilt. Have recently done complete tuneup and eliminated a similar jerking when accelerating rapidly at higher speeds. could the torque converter be involved, and if so how could it be tested and fixed?
The problem may be due to a dirty throttle position sensor.
Thanks–will check it out.
In 12 years, a lot of oil and carbon particles could have gone through the pcv valve into the intake tract. It can affect the tps, idle air control valve, and throttle plate and bore.
Clean the MAF (Mass Air Flow) sensor with MAF cleaner. Clean the rest of the intake tract (and the sensors) with Carb/Throttle Body cleaner.
It’s cheap, and the benefits can be significant (though, not guaranteed).