My instructor at the technical school sprayed my throttle plate (butterfly) with cleaning fluids to clean plate and throttle body. There was just some carbon buildup inside.
Later we (students only) changed the spark plugs with NGKs that came originally on the car. No torque wrenches were used. Coil packs for cylinders 4 and 6 had been incorrectly connected and led to P0300. We corrected the problem. Engine ran for a minute or so on 3 or 4 different engine starts with the issue before we swapped connectors.
A couple days later I notice that while my car is stopped while in drive, the car engine does a single shake. It happens again the following day. Both times were after I had taken short trips and warmed up the engine. Just yesterday I took the car on a long trip and every time I came to a stop, the single shakes occurred often. So it definitely happens after engine is warmed up.
Runs fine on the highway. I even get the same fuel economy as before.
My car has 149600 miles.
My car has an automatic transmission.
Hi there. There could be an issue with the fuel system or with the ignition system on your vehicle. It seems that the engine is having a minor misfire. Check the spark plug wires and see if any of them have a split in it causing them to go to ground. Also, make sure that the wires are attached to the spark plugs correctly. The engine and transmission mounts will also make the bumping feeling as the engine is hesitating from high mileage. Check to see if the mounts are loose or worn. If you need further assistance with your engine shaking, then seek out a professional, such as one from Your Mechanic, to help you.
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