I bought an 07 3.0 ranger sport with 125k 6 months ago. Since then.. all oem. New fuel filter / air filter old one rusty and really dirty inside. Replaced noisy cam synchronizer and position sensor. Plugs,wires,coil. Pcv valve. Cleaned iac, maf, throttle body. Still having a light misfire at idle.

Bought ultragague. Cold start long trims 14% bank 1 and 12% bank 2. Short term trims negative. Increase rpm to 2,000 long trims drop. Might still be in open loop.. how do I tell on the ultra gague?

Once warm long trims settle around 8%. Increase in idle makes very little change if not slight increase in trim.

So... intake gasket leak?
injector issue making the banks different?