460 cold idle

[aadd]

I have a 460 and every time i start the engine, wether it is hot or cold the revs rise and fall for the first 5 mins.This means when i am driving i have surges and lulls in power. After about 5 mins the problem clears and it drives spot on. Any ideas what the problem is and how to rectify it PLEASE

[Paul.C]

Hi , I have a 480 Auto which had simalar symptoms. Mine were resolved by having the MASS AIR FLOW SENSOR replaced. As well as the erratic tick over I had blackened plugs & distributor terminals, it also used to surge if going down hill with trailing throttle. This replacement appears to have solved all.
I have also noticed that the O2 SENSOR was replaced not long before I purchased the car I am unsure what symptoms that sensor shows when it goes wrong but it may be worth having both checked. Mine was diagnosed by computer after I had pulled my hair out trying everything I could think but failed miserably!
Good Luck.

[aadd]

Thank you I will try that tomorrow