ENGINE SHAKING UNDER 2000RPM (no mount)

[Gregos]

Hi,

(once again i am french, so allow me some mistakes 😉 )

I bought a LS430 uk car, few months ago. I decided to make a first basic service, by doing :

- spark plug : same as genuine, and same as old ones : DENSO same reference   +  Oil / filters etc...

Just after, engine started shaking.

It only happens between 1000 and 1800rpm when i am driving at stable speed. Sometimes, it runs very well, sometimes, engine is having like some short cut.

Then, i just need to push accelerator and go over 2000rpm to stop it. Sometimes also happens when stopping at red light. I can feel those little shaking from engine.

= no light code, full power, nothing else.

it is not engine mount, it is from engine, definitely. I was thinking about the coil connector plug, I changed one, which seem to be damaged.

But still same problem. As it happened after changing plugs, I don't understand how it could come from anything else.. 😞 

Thanks for your help.

[runsgrateasanut]

As a Francophile great symapthy for the terrible Notre Dame tragedy.

Could the Car be running on 7 cylinders?

It's easy to splice a Spark plug Lead, when putting back the covers as I found when I replaced my own.  I was surprised to see how easy this could happen. 

Another thing, are the Spark plug leads seperated as they should be and not overlapping in some way which might affect performance? If you haven't touched the Lead set  then not the problem.

Just a few thoughts.

 

[GrahamG]

Even though no warning lights on the dash I would definitely check for any codes and all the better if done with Techstream.

[Gregos]

thanks guys.

runsgrate : I will check again, but plugs have been fitted by a mechanic who owns different V8, so hope he did correctly

graham : yes, right, i'll check with scan machine if anything wrong

but i am sure, i am not the only one who met this

 

 

[Gregos]

good morning,

today, i started engine, and vsc + light appeared.

Now engine is running on 7 cylinders, engine shaking.. i'll check engine code ASAP..

[messi]

It's the coil packs, best to change then all