My truck started accelerating past 35 earlier this week and then it started shuddering, with that feeling a vehicle has when it doesn't have any gasoline. I could not find anything visibly wrong in my truck and the sputtering/shuddering problem did subside as fast as it started. However, several other problems developed when my truck first developed the problem. There is now a vibration in the gas pedal (only when I accelerate) and the pedal has become resistant to touch. The truck is normal in its idling and still drives, but there is less power and it sounds rougher than before. Two weeks ago I replaced the PCV valve and I have been adding Techron for three weeks. I checked the butterfly valves in the carburetor and found them to be perfectly clean. The distributor looks in good condition and the distributor cap has not moved. I have replaced the air filter with a new one, as well as the fuel pump, fuel filter, fuel sock, and the gas tank clean when I installed the fuel pump. I saw some minor cracks in the air hoses, but they did not look serious. All of this was done within the past 4 weeks. What is your advice for my next step in repairing my truck?
Hello there, thank you for asking about your car. The first thing that comes to mind is a secondary ignition misfire (spark plugs, wires, etc.). An ignition misfire is most noticeable under load and can be felt as a shudder if it is severe. Another thing comes to mind is torque converter shudder, which occurs right before or after converter lockup. Modern vehicles have a lockup torque converter to improve fuel economy. Of course, there are many other potential causes for your problem as well. Anything from a worn u-joint to a failed engine mount could cause the problem. The only way to know for certain is to have your vehicle inspected by a trained professional, such as one from YourMechanic, who can inspect your sputtering problem and make any necessary repairs.