I tweeked my cam timing to a little over 6 degress retarded on the exhaust cam at the weekend, i turned the car over numerous times by hand, there was not contact between pistons and valves. At first i thought it was fine but i started it again last night and there seems to be a very minor miss fire, have i bent a valve or can the retarded timing cause this. It revs fine, its idle is just a little unstable. I have just fitted underdrive pulleys could it be these?

 

Yes it could be the retarded cam timing affecting it, as it will need a tweak to the map now as the cylinder fill at idle will almost certainly be less than it was, so if it was a touch on the rich side anyway it could now be just that bit richer again by enough to make the idle wander a touch.

 

Thank you very much Chip, my mind is now at rest, the map that is on there is for 97Ron fuel and it currently has 95 in it, the plugs are very sooty. I will switch the map to my 95 one and see if it improves.
Thanks Again

 

I never let retards near my car.....

 

It probably needs a new map to suit the new cam timing, not just a different octane map.

 

I can see this getting expensive lol
I did chuckle to myself when i typed out the thread title!! Problem is im the retard