Hi a mate has just changed his head gasket on his 2wd sapphire and now it won't run on all 4.
Good spark on cylinders 1 and 4 but very weak on 2 and 3. It has fuel on all 4 cylinders and has had rotor cap and leads replaced but still the same.
Ran on 4 cylinders before changing gasket.
Any ideas what this could be ? Totally standard engine with no upgraded parts.