VT Jumping Violently when foot down from 0

[jamiev90]

Hi Guys,

Have a bit of a dilemma, My VT calais (v6 3.8ltr Ecotec) is having abit of an issue accelerating at low revs?

It seems that if i roll off and drive like a sane person and slowly start to accelerate its fine.
But if i put my foot down even half way, (from stationary) say at a stop sign or something, it jumps and has no guts at all (not that the ecotec ever did have guts..)

Now this has happened before and my mechanic replaced the spark plug leads (12 months ago), so i followed suit and replaced my spark plugs about a month ago, and only replaced the leads this afternoon.

It hasn't fixed it though! does anyone have any more ideas as what could be causing this.

Thanks,

Jamie

[Longman]

I know you replaced your plugs, but might be worth checking them again to make sure they didn't crack when being tightened (this has happened to me). Also make sure the leads are connected in the correct order.

If plugs/leads are OK, the next thing I would check would be the fuel system. Get your mechanic to test the fuel pressure, it's possible your fuel pump is on the way out or your injectors could be blocked.

[jamiev90]

brand new fuel pump about 2 months ago T_T, and put injector cleaner in for the sake of it when the issue started, and yeah, i'll throw some more spark plugs at it

[Longman]

Hi mate,

I didn't mean go an buy new plugs off the bat. Check the new ones you just put in as it only takes a little bit of over tightening to crack the ceramic part of the plugs which then leads to the problem you encountered.

When the same happened to me, I found one of my leads had gone, so I replaced the plugs and leads only to find the same problem occurring. I rechecked the plugs and found I had cracked one.

[BECS]

Coils or dfi seen a vs with a cracked coil do this.

[Tsunamix]

Busted engine mount.