Chefkoepp

Intermittent engine vibration / shudder at idle solved! I have a 2014 tahoe. 5.3L and have worked on this for a year. You don't have an engine problem, you have a maintenance problem. This is a multi step process. ******REMOVE BATTERY CABLE****** 1)The mass air flow sensor needs to be cleaned with crc mass airflow sensor cleaner about every 10k miles; especially if you have a k&n filter. Oil Coates it and it miss reads. 2) you need to remove the throttle plate (4 10mm screws) and clean the front and back of the plate thoroughly with crc throttle body cleaner. After cleaning, take a clean towel, spray cleaner in the throttle body and wipe it out with the clean towel. This needs to be done every 10k or so miles or when you notice the shudder, or it starts shifting hesitantly. Verify the wire connection is in good condition and no wires are loose. Verify the silicone gasket is in good repair and clean. I f not replace it. **********(IMPORTANT)************** After re attaching the throttle plate to the throttle body you must run the recalibration sequence for the engine. 1)re attach the battery cable. 2)turn the key to on (not start ) for 15 seconds. 3) make sure all accessories are off. 4) start truck and let idle till it fully cycles. About 8 to 10 mins. 5) turn engine off remove key 6) again put key in and turn to on posit in for 15 seconds 7 start car and drive at a normal pace. Don't race it. Take it on highway and it will continue to relearn shifting points. Additionally, you most likely also have water in your tank due to ethenol absorbing humidity from the air. You need to run 3 or 4 successive tanks of water remover or HEET through your truck. Small water slugs also give your truck a shudder. But the easy way to tell if it is water is to park face down on a steep hill and the water will go to the front of the tank and not pool around the fuel pump. If you still have the shudder, it's the throttle plate and mass airflow sensor. It's not that hard to do this so every 10k just do it. It will also make your vehicle shift better and reduce the hum of the active fuel system management. Problem solved.