98 F-150 5.4L 4x4, Under about half throttle starts to vibrate?

While traveling if I give it some throttle (about half) to accelerate it starts to vibrate but not seem to gain speed. If I punch it it takes right off and feels fine. Could this be a tranny problem? Torque converter maybe. Seemed to start out of the blue just now. Ran just fine last time I drove it. I have installed a hypertech programmer, K&N fipk, and just had new fuel filter and spark plugs installed and transmission was just serviced by Ford. It really feels like something is slipping under half throttle and hooks up only under heavy throttle. I've been running the "firmer shift" setting on the hypertech for years. Could this have worn out my torque converter? Any insight would be appreciated!! Thanks.

3 Answers

  • 1 decade ago
    Favorite Answer

    Have you checked the TPS Throttle Position Sensor? You can check it with a VOM and looked for a flat spot on the meter as you move the sensor slowly

  • 4 years ago

    loss of brake tension is yet another difficulty that could ensue while it is composed of the brake equipment of your motor vehicle. you may tell while this occurs via fact once you press on the pedal that controls the brakes interior the motor vehicle, you come across that the pedal particularly is going promptly to the floor. There are oftentimes 3 themes that could be happening, beginning from a delicate difficulty to a extreme trouble that could consequence in 1000's of greenbacks in upkeep:Now to restoration this undertaking my buddy the 1st element which you will desire to do is examine the brake fluid interior the motor vehicle. there's a reservoir that sits atop the grasp cylinder, or maybe to the part. determine that brake fluid is going all the thank you to the fill line. If it would not basically upload extra fluid. 2. Now, there could come a situation wherein air certainly enters into the brake fluid interior the reservoir and works its way into the brake lines and strikes by the equipment. this could be a no longer effortless situation. the final answer for this undertaking is to take the brake equipment and "bleed" them. 3. the main complicated and high priced of all achieveable circumstances is that the certainly grasp cylinder area of the brake equipment could be defective. there is not any rapid restoration or effortless fix kits for this occasion. you will ought to certainly replace the grasp cylinder, and that may no longer inexpensive - rather notwithstanding if that's professionally completed.

  • 1 decade ago

    Raise the hood at night and look at the spark plug wires and see if you can see the sparks.. if so get a good set of wires and replace them.. the nightime no hood lite test really works.. look at it at an idle.

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