Engine shakes when idling

Hi, newbie and ned help. Jimny Automatic, 05 plate. Engine shakes violently on startup but with a few revs and a bit of luck starts to run alright. When idling at the lights the engine sounds like it is going to stall, has on a couple of occasions but usually manages to keep itself going.

Been to the garage: Had the cam and crank sensors changed - it was not that. Had the brake/fuel thingy changed which lives under the brake pedal and regulates air and fuel, the mechanic thought air was getting into the engine - it was not that. Mechanic then changed what would have been the distributor in an older model thinking the rotar arm might be at fault or one of the pick-up points - it was not that.

Does anyone have any idea why my Jimny is pourly.

May just want a service , oil + filter , air filter ,plugs fuel filter etc

Car was last serviced about 18 months ago. It has done 46,000 miles and still has the original spark plugs in but these are supposed to be guaranted for 60,000 miles.

Could be its leaking air causing a lean mixture somewhere on the intake side of the engine and the idle control valve is trying in vain to compensate you dont mention which engine it is single or double overhead cam ??

It is a single overhead. Spoke to 2 mechanics today, (different garages). One said there could be a dodgy spark plug and simple replacing them might do the trick. Another mechanic said it sounds like the fuel filter (which is inside the fuel pump which is inside the fuel tank.)

Without all of this advice I wouldn't know what to do so I thank everyone that is reading but if anyone could think as to which option I should start with that would be great.

Given the two choices, you can change the sparkplugs easily enough, the fuel filter needs tank removal, and rarely give trouble.

The plastic PCV valve at the cylinder head (not sure where on a single cam) with a thick rubber pipe that leads back to the inlet is another possible culprit.

Whilst the sparkplugs are out, do a compression test.