What causes engine shaking in older Jaguar 6-cylinder engines?
2 Answers
Older Jaguar 6-cylinder engines may experience shaking due to the following reasons: 1. Excessive engine carbon buildup: After a certain mileage and duration of vehicle use, some carbon buildup is inevitable. Excessive carbon deposits can easily cause engine detonation and shaking, adversely affecting engine power output, significantly increasing fuel consumption, and polluting the environment. 2. Unstable oil pressure: Typically, abnormal fuel pump supply pressure or incorrect readings and poor performance of the intake pressure sensor can cause body shaking. In such cases, it is necessary to conduct a comprehensive inspection of the vehicle's fuel supply system at a certified service station to determine if there are any leaks and identify the cause of the shaking. 3. Abnormal ignition system: This situation may be caused by severe spark plug carbon buildup, low ignition voltage, or poor spark plug ignition performance, which are also major reasons for vehicle idle shaking.
I'm an experienced auto mechanic and have worked on many old Jaguars. If a six-cylinder engine is shaking, it needs careful inspection. The most common issue is the ignition system—worn spark plugs or excessive carbon buildup can cause misfires and vibrations. You should remove and check the spark plugs; if they're eroded or the gap is too wide, replace them immediately. The ignition coils might also be faulty—older cars often have poor-quality coils, so don't skimp on replacements. Loose or cracked engine mounts can make the whole engine wobble noticeably; if it feels unstable when you shake it by hand, get it fixed. The fuel system is crucial too—clogged injectors or low fuel pump pressure can lead to uneven combustion. On the intake side, vacuum leaks or a dirty mass airflow sensor can disrupt the air-fuel mixture. With an older car like this, carbon buildup can cause uneven compression and erratic power delivery. I recommend taking it to a professional shop for diagnostics—they can scan for trouble codes and pinpoint which cylinder is misfiring. Safety first—don’t wait until a small issue turns into a major repair.
