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Q: car does not accelerating smoothly until it reaches 30 mph.

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The rpm's will not go over 2000 rpm's then drop 1000 and then go up and down until the car reaches 30 mph. You can floor the pedal and the car still will not move.After 30 it accelerates ok. I can sometimes shut the engine off and on the restart the car runs ok but not always. The problem does not show a code with a meter plugged in and traveling. I will get an engine light for a e-vap condition that will go on and off. The engine idles smooth and 600 rpms, I have changed the fuel filter, o2 sensors, fuel pump and map sensor. Could it be tps sensor?

My car has 115000 miles.
My car has an automatic transmission.

Hi there:

The throttle position sensor is typically mounted to the gas pedal, and essentially translates the movement of the pedal (speed and position) into voltage, which tells the car’s computer how much fuel to supply for engine acceleration. Due to this fact, the issues you’re having with your Blazer could be caused by a malfunction of this component. However, it’s also possible that under the hood parts like the mass air flow sensor or other emissions related sensors might be causing the same problem. To be certain, it’s a good idea to have a local mobile mechanic complete a car is hard to accelerate inspection; so they can diagnose the issues onsite and make the right repair recommendation.

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