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[mega3.0v6]

Hi all i asked the other day about misfire. Well i wouldn't call it a misfire just like a  misfire. I sadly sat outside this evening when i got in from work and watched my rev counter fluctuate up and down only a little but enough to hear the engine hunt a bit. The thing is it runs fine up till it gets warm so when say i come up to a roundabout and drop down to 2nd and pull away it judders abit between 1k 2k after that it is fine. I have had TECH2 plugged in with no faults found but on the menu that was on the screen something was going ACTIVE DE ACTIVE i asked the guy do you think it is the crankshaft sensor on its way out and he said "could be" i thought to myself thanks mate but said "it cant be as a fault code has not shown". So please could someone help me as i need to get this fixed by Friday doing a 300 mile trip and i dont fancy breaking down.

[TheBoy]

What was going active/deactive?

if no fault codes, check HT side, particularly oil in plug wells.

Also from symptoms, check for air leaks

[mega3.0v6]

I have changed leads plugs. I cant remember what was doing the active bit i think it said SECONDARY or something like that.

[mega3.0v6]

btt

[Marks DTM Calib]

Sounds like whoever it was that was using tech2 was not to compitent.

I assume they were looking in the live data and could see one of the control loops going active/deactive. They should of also checked the coolant etmp reading and ideally a few other parameters.

I would of also of carried out a few actuator tests (EGR etc) and taken a vac reading as part of the diag.

[mega3.0v6]

btt

[mega3.0v6]

Update: Had car plugged into a snap on machine scrolling down the mechanic notice my car was running LEAN/RICH could this be my problem i changed fuel filter yesterday aswell. As i looked underneath and looked like it had the original filter on it as it was a GM one and was rusty so any ideas Please.

[rickyboy]

Similar post on the forum at the moment.  Your o2 sensor is meant to switch constantly between Lean and Rich if it is working properly.  

[podd37]

Hi Mega. Had any joy yet? Mine has just started doing the same thing and only when warm. It's also doing it under full load in say 5th when overtaking. Very disconcerting!

[Richard A]

Had the very same problem in February, engine hunting and slow pick up, after 1500 rpm ok, 'Dr Omega' checked engine with a 'Tech2', lean/rich, vacuum leak, after some checking it was the crankcase breather (drivers side towards the back) the rubber pipe had perished plus I had fitted new leads and I may of broken the already weaked pipe, cut back pipe cleaned the very small breather hole in the brass connector. Instant difference - problem sorted. All the Omega engines are very sensitive to vacuum leak problems, please check then recheck again.
regards
richard a