My VLT has developed a issue. At idle it misses heaps and also at cruise throttle. On the boost gauge, anything under 10Hg vaccum it runs like poo but when I'm over 1/3 throttle (accelerating) or above 10Hg, 0Hg or even boosting it runs completely normal. I thought it might haev been a leaking injector making it cough at but when i'm accelerating I'm using the extra fuel, but you'd think my fuel economy would be crap and there would be fuel coming out the exhuast which it isn't. I have recently changed plugs and also leads to fix the problem but it didn't stop. Any ideas.

i think you may have a leak in your intake pipes etc ok get some sopey water and spray around the intake ports etc and check for bubbling, i do it with carbie cleener and when the revs pick up you know you have a leak. be carefull tho it is highley flamibol so dont spray too much around the exhaust or hot parts

You running after market ECU or Factory?

Sounds like a Vacuum leak to me.

If its actually misfiring then it might be something worse but if its just rough on idle then it could be anything from a dirty injector(s) to needing a tune. VLT's don't like to stay in tune for very long Some original photos have not been recovered yet.

Tell me about it. Standard ecu. I was thinking vaccum leak but it sits at 20Hg at 800 rpm and when you create your own vaccum leak such as taking the vaccum line of the fuel reg, the engine will just idles higher, doesn't make it start missing. Besides, I haven't taken anything apart for it to not seal properly and all the pollution/vaccum hoses are on. Tried spraying CRC over the intake maniold anyway but no luck.

bodgy o2 sensor?

I had that same problem in my N/A VL.... It was one of the sensors, i can't remember which one though.

Another vote for the O2 sensor here. Does it make a difference if you unplug it?

had the same problem in my converted vlt, try undoing the bolt that holds the dizzy in place and turn it a couple of mm anti-clockwisethen tighten bolt back up.

it can b a number of things from leads n plugs 2 a leak air flow meter or even crank angle sensor on the way out

Try another AFM man might be that or check your ECU errors see how you go.

Checked ecu errors and unplugged the O2 already and nothing got better. Narrowed it down to the coil was firing 5 times then leaving a gap then firing another five, ended up missing number four plug?? Put a new crank angle sensor in and it got better, then put a new CAS plug on the wiring harness (wires were green and yuk) and now it's heaps better. Bloody CAS. I wish I had shares in them.

Good old CAS VL's worst enemy hehe Some original photos have not been recovered yet.