VT Sputtering at idle

[madrx3boy]

Hi everyone,

My VT 3.8 Ecotec has had a bit of a sputter since I got it 1.5 years ago. For a long time I never really noticed it unless I walked round to the back of the car, then I could faintly hear the exhaust sputtering (sounds like a pffft sort of noise). I didn't think too much of it at the time

But lately it's been a lot more noticeable - now I can feel the car shaking at idle - and now it's really starting to bug me. One by one I've replaced the air filter, plugs, and leads but it's still doing it.

I can't say I notice anything while the engine is under load - maybe a slight decrease in performance, hard to say due to the fact that the problem was already there when I got the car, and partly because it's gotten worse slowly over a long period of time.

I've got a couple more ideas of what it could be, but want to get some advice before I start replacing parts unnecessarily.

I'm thinking either: Coils (How can I test them?), Fuel Filter, Cracked vacuum hoses. Although I would have thought that if it was any of those, then it would be even more noticeable once I open up the throttle more and more?

Any ideas will be much appreciated!
cheers

 

[Nut Kracker]

Why not think out of the square for a change and check that the muffler or cats aren't blocked.

 

[VTSS304]

As Nut Kracker said it could be a blocked exhaust section. Also you could try something like and upper engine clean (comes in an aerosol and you spray it into intake while the car is running, then let it sit for 15-20 mins, then it will be hard to start and will blow smoke for a few minutes but then should either improve from before or go back to how it was) It could still be a coil because at higher revs the spark might be strong enough to jump the break and run as normal. Possibly a partially blocked injector?

 

[madrx3boy]

cheers guys will check it out on the weekend