Hi guys.
I had a look at a 2008 Vauxhall Vectra 1.8 petrol Z18XEP, yesterday.
The car is suffering with flat spots. there are no fault codes stored. I test drove the car with my scan tool connected and recorded a drive cycle.
This was my first step in diagnosing the problem. I haven't checked the basics, compression or timing, firstly because I never had the car long enough and second of all I don't think the symptoms merit starting that far back.
I did ask to see the service records and records and receipts of work carried out, and parts.
The car has covered 70,000 miles,
Going over the live data recorded during the drive cycle the only thing that jumped out was the throttle position shown as either Idle, partial load or full load was dropping down to invalid, which shows the car going flat. However other parameter's seem health, such as throttle position in volts, acceleration in volts and relative data, I may be missing something. I don't know how to post my data on ukat.
The cars service records are up to date but there was no signs of the spark plugs ever being changed, which is what i was looking for. I removed the plugs and they plugs were deteriated bad, they was how can I describe it, slight melting, and had different gap sizes from the wear.
I changed these straight away and was expecting the problem to be gone but still the goes flat.
I am going back to the car on Monday but am thinking what route to take.