I have a 2003 dodge Dakota rt 5.9l that I changed the head gasket on about 3 months ago an now it losses power and backfires then runs fine. Itll keep doing it off and on the whole time while drive. What could be the cause if changed spark plugs they keep turning white an oil is black as soon as I do an oil change.
That could be a fuel pressure problem, among other things. Have you done compression and fuel trim tests? If not, that’s what I’d be doing first w/this problem. There’s no check engine light, right?
Just for the downstream o2 sensor sense I have no cats but the upstream ones r good
Then you should have a check engine light on . . . unless you’re a sneaky devil and used an “oxygen sensor simulator”
Why are you so sure the upstream oxygen sensors are functioning correctly . . . ?