1HZ 4.2 (no turbo) starts and stops with a bump

[CanAmSteve]

Hello and thanks for letting me into the club. I've just purchased a well-maintained 2008 4.2L non-turbo LC 76 SW. It has 300K km - mostly highway - and has been well-maintained. It runs flawlessly, but when starting or stopping the engine there is a momentary vibration or "jump" as if it leaps to life.

Is this normal or an indication of an issue? Could it be a worn motor mount? Otherwise it starts immediately and runs sweetly. Many thanks

 

[nick_the_fish]

Hi Steve,

Welcome to the forum.

I've got the same engine in mine and it doesn't start or stop with a jump, so i'd say it isn't normal. But other than that I can't be of much help i'm afraid. Engine mount certainly seems like a sensible place to start. Theres a lot of space in the engine bay so should be easy to poke your head around in there and have a look.

I'm sure someone will be along soon with some more suggestions.

Nick

 

[GeekOKent]

I don't seem to have any jump or any vibration either. 1hz about 100k miles

 

[StarCruiser]

You could try gently jacking up the engine from underneath with a block of wood to spread the jack force. If the engine soon starts to lean left, right, front or back, you’ve got a mount that’s gone bad or parted company. There’s three, one each side and a gearbox one. If it doesn’t lean it’s not so easy to spot but I’d say your issue is with engine mounts as already mentioned.