I have been owning this 99 T-Reg Astra since last Sept. Was running like a dream until last few weeks. When I was in Scotland 3 weeks back after having driven from Ipswich, all of a sudden, the engine management light came on. I stopped the car and it went off after a while. All the way back from Edinburgh to Ipswich, it never came back on again until few days ago. But whenever it will come, it will stay for sometime and then go away. The car would run fine even when the engine management light would be on.

Last Tuesday, when I was driving back from work, i noticed the engine management light to come on and I could feel that the car was rough/chuggy and there was a lot of vibration. I stopped the car on the roadside, opened the bonet and saw that the engine was vibrating and also the rear exhaust pipe was also vibrating.

Took it to my mechanic friend, who thought it could be a problem with either the spark plugs or the coil pack. He tried replacing both but didn't help. He then pointed to the fact that it could be that either the valves or one of the cylinders could have gone bad but couldn't say for sure since he doesn't have the equipment to run the diagnostics.

The air con also has been temperamental. Had it regassed beginning of this summer and it would cool well since after. But it had problems where the air con light will go away on different fan speeds and stay on some fan speeds. when the air con light goes away, even the rear defogger light wouldn't stay on. Since last week, the clutch hasn't been engaging at all, hence no cooling. The air con light would come on at times and not come on at other times. Suspecting low on gas, took it to where it was regassed beginning of the summer and they confirmed the gas levels to be ok. not sure whats going on..

Could the air con and engine misfire problems be related?