VAUXHALL VECTRA ENGINE SYMPTOM

Was Driving Yesterday And Started Hearing Knocking Sounds When I Pulled Off And When I Changed Gear. Shortly After The Car Car Just Revs Out...

Can You Please Tell Me Engine Idle Speed On 1.8 Petrol Sri 56 Plate Currently Sitting At About 900 Rpm

Start Up Fine But In Few Sec It Off If It Is Parked For Long Time Ie 17 18 Hrs And Require Long To Start With Out No Fireing Some Time Bty...