boojak87
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- VT Series II SS 5.7L
Hi all. Just wondering whether a stuffed Throttle Position Sensor, Idle Air Control Valve and/or Mass Air Flow Meter Sensor could be the cause for a rough idle when sitting at lights in gear and slightly poor fuel economy? I'm sort of relunctant to try absolutely everything that someone's mentioned to me, because it could be a never ending thing until i replace practically everything in the engine! Just wondering what you all think:
Symptoms on my Ecotec VS being:
- Rough idle ONLY IN GEAR, when in 'N' and 'P' idles smooth. The idle doesn't drop, (hovers around the 800rpm mark) and doesn't threaten to stall at all, however the car has a constant rumbling feeling when sitting at the lights (like sitting in a carby v8), the slightest acceleration (even just 100rpm more) gets rid of it and it's smooth again.
- Poor fuel economy (hovering around the 14.5L/100kms area) was up to 15.5L - 16L at a stage before injectors were treated with a bottle of injector cleaner.
- Not the greatest of pickups (especially once engine and fuel is warm), almost sort of hitting a flat spot in 2nd, when going between 2000 to 3000rpm, then you get jolted back into your seat a tad more once over 3000.
- Don't know whether this is significant or not but after a night of sleep and awakening on a cold morning first start-ups can be a tad rough. It starts almost instantaneously like normal but it chugs for a couple of seconds before it revs itself up to 1500 for a little before finally settling to normal idle speed. When outside of the car during the first start up on a morning a ticking noise can be heard from the engine for the first 30 seconds or so. Like i said, i don't know whether this is significant or not but just thought i'd mention it as the more information given, the better.
Just another query, could the catalytic converter be the cause of this, i have stumbled across the theory once or twice but, i'm unsure!
Thanks all, any feedback or general comments on what i should get checked would be awesome.
Thanks again, Boojakz.
Symptoms on my Ecotec VS being:
- Rough idle ONLY IN GEAR, when in 'N' and 'P' idles smooth. The idle doesn't drop, (hovers around the 800rpm mark) and doesn't threaten to stall at all, however the car has a constant rumbling feeling when sitting at the lights (like sitting in a carby v8), the slightest acceleration (even just 100rpm more) gets rid of it and it's smooth again.
- Poor fuel economy (hovering around the 14.5L/100kms area) was up to 15.5L - 16L at a stage before injectors were treated with a bottle of injector cleaner.
- Not the greatest of pickups (especially once engine and fuel is warm), almost sort of hitting a flat spot in 2nd, when going between 2000 to 3000rpm, then you get jolted back into your seat a tad more once over 3000.
- Don't know whether this is significant or not but after a night of sleep and awakening on a cold morning first start-ups can be a tad rough. It starts almost instantaneously like normal but it chugs for a couple of seconds before it revs itself up to 1500 for a little before finally settling to normal idle speed. When outside of the car during the first start up on a morning a ticking noise can be heard from the engine for the first 30 seconds or so. Like i said, i don't know whether this is significant or not but just thought i'd mention it as the more information given, the better.
Just another query, could the catalytic converter be the cause of this, i have stumbled across the theory once or twice but, i'm unsure!
Thanks all, any feedback or general comments on what i should get checked would be awesome.
Thanks again, Boojakz.
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