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I have had problems ever since I purchased the automobile. 120,000 miles with a full service history. At an idle engine speed of around 650rpm, whether the engine is hot or cold, there are frequent engine vibrations that may be felt in the cabin. It momentarily transforms into a diesel engine. It gives the impression of a misfire, but it is not. Utilised an OBD tool to examine the operational data of a well-functioning cylindrical component. The acceptable range for reference values is between 0 and 2.5, while a misfire is indicated when the values fall between 7.5 and 10. My vehicle often hovers using three to four separate cylinders, sometimes reaching a height of 5.50. The coil packs were replaced as a precautionary measure, but there was no noticeable improvement. Replaced the spark plugs with NGK IFR6D10. The engine exhibited improved sound and seemed to be in better condition thereafter. I conducted a resistance test on the ignition leads using a multimeter, and all of them had satisfactory results. I reconnected everything with a distinct audible click. The engine wiring seems to be in good condition with no signs of corrosion or improper bends. The PCV hoses around the valve covers remain undamaged after replacing the valve cover gaskets. I am uncertain about which aspect to investigate further. Is the injector malfunctioning? How can I verify them?

Any recommendations are appreciated. Thank you.

When were the engine and gearbox mounts most recently replaced?

Approximately 60,000 miles ago, I am uncertain of the precise year, but I have it documented on a service sheet. Second set of tyres on the vehicle

Have you conducted an inspection of them? It is quite simple to inspect and rule out the possibility of oil leakage from the engine mounts or a rupture in the rubber on the gearbox mount during the process of identifying the problem.

Another cost-effective and enjoyable way to inspect the engine mountings is by giving the engine a vigorous rev while carefully noting its movement.

Engine Crankshaft Damper
The crank pulley wheel is installed with a rubber bushing that might deteriorate and cause instability.
Common on M113 engines without superchargers

In the first part of this piece, I said that I conducted an idle smooth running cylinder test using my OBD scan tool, which yielded approximate idle figures. Engine mounts are not electrically interconnected and are not related to the electrical system.

https://www.youtube.com/watch?v=DgVagHh ... b_imp_woyt

Approximately 50 minutes into the event

Perform a smoke test on the intake system, and it is likely that you will discover several leaks in the vicinity of the MAF sensor/housing.