see prior thread, regarding cracked head. Jeep ran fine before head replacement, passed smog, no check engine light, smooth running. , after new head, jeep ran ok first several miles with the new head (head replaced due to coolant leak). Now it runs rough, (missing) check engine light on, code says 3 is the culprit. swapped injector, no change. new coil pack, no change, new spark plug no change.

is there a diagnostic test to make sure the computer is properly sending signal to the coil pack? any other suggestions?

Want to take jeep to Death Valley Thursday, two days from now. but at this point it looks like a no go.

Any diagnostic help will be greatly appriciated