I would 2nd that.

Also one of my old tech notes from some years ago below

Vectra & omega V6 engine running issues

The system is Bosch 2.8.3 sharing similarities with other GM V6 variants. The vehicle supports excellent serial communication capabilities and Autodiagnos offer software for this purpose. When choosing serial diagnostic equipment I appreciate cost will always be a factor but I suggest you consider complete vehicle access systems.

From our experience the growth in SRS & ABS repairs present a profit centre not to be turned away.

The V6 EM power plant is not a cheap one to maintain. Spark plugs & HT lead replacement is a common occurrence @ approx. £200.00 excluding labour, which may add £75.00 with basic diagnostic checks.

The main problem with HT is corona ringing, which is often quite severe @ low mileage, (15-3,000 mls) oil leakage and spillage do not help.

The EGR valve is easily accessible and we strongly recommend modifying by manufacturing a blank gasket to prevent passage of gasses. This method avoids Mil lamp errors from the lift solenoid and potentiometer if left disconnected.

A noticeable improvement in light and mid range derivability can be expected.

Software modification is another option for increased midrange performance; this can be installed via the serial port.

As with many other vehicles the most common problem is hesitation especially at transient and light throttle.

Check DTCs, but don’t omit the preparation to HT first, it’s a labour intensive exercise to replace components so fit the OE products first time explaining the benefits to the customer.

Check both Lambda sensors for active switching & frequency. Zerconia sensors should have crossing amplitude of 800 MV with a frequency over 1 Hertz.

Next take a look at the air mass meter, which is a thick film type as opposed to an exposed wire filament.

For a complete evaluation you are going to have to plot the output using a oscilloscope (waveform (1) during a snap throttle test. Pay special attention to the rate of amplitude of the primary peak and secondary peaks. The output is very critical 4.5 volts should be expected, a drop of 200 MV will present significant under fuelling on acceleration, however if the air intake or exhaust are restricted this will directly effect the flow rate of the air intake. Just as incorrect valve timing will. Remember this engine has two cams per bank with 24 valves, they all need to be singing from the same hymsheet.

It is worthwhile on high mileage vehicles, removing the injectors & testing on a flow bench before servicing. A decrease in injector performance is gradual and often not detected by the customer, together with the attention to HT and Lambda sensors; attention here can transform a lacklustre V6 into a powerful tractable engine.

One of the more intriguing problems with GMs V6 was on an Omega, however the problem was a misfire @ or around 3600 RPM.

The effects (symptoms) were erratic dwell and injector pulse control. Applying the oscilloscope to a break out box (waveform (2) and monitoring the crank angle sensor (CAS) identified a defect in the wave form pattern.

This defect was static within the signal pattern just after the TDC point.

sorry for bringing up an old thread but i am having the same probs as the OP. I hope this fixed your problem mate. can someone please give me instruction on how to do this.

Any replys are appreciated.