Purplemaroz28

It only happens at night when its cold, but itll stumble in first gear and it is defintiley missing. At idle u can hear it stumbling. And it defintley smells rich. Is this just as fouled plug or wire or do i have the opti spark blues.. no problems during day. by the way the optispark is new with the engine and so are all the spark plugs and wires and my a/f is roughly 13.7-15.1 at idle. and 12.8 at wot

Injuneer

When the ambient air temp is cold, or when the engine is cold, or both?

Purplemaroz28

it only happens when the outside tempature is cold and after the engine has warmed up. But then this also only happens EVERY now and then and is not a contioniouse problem so it is hard to have a mechanic diagnose it.

Guest47904

Pull the coil off and inspect it closely for any white marks on the black insulation or cracks. You could also mist it with a spray bottle of water to look for sparks at night.

You should also scan it to see what the sensor readings are doing from cold to hot like ECT or IAT.

Purplemaroz28

any more advice trying it tommrow

Purplemaroz28

my passenger side o2 is alittle lazy going to replace that and see if there is any difference. Still trying to get cable for scan.