Three Codes on 2000 jeep Cherokee 6cly

Question

Engine runs great once I am moving, But at Idle Misses, coming up with codes #P0302, P0303 and P0171, Have done a complete tune up.what can it be?

Answer 1

P0302 Misfire cylinder number 2

P0303 Misfire cylinder number 3

P0171 Fuel trim lean bank 1

When there is a misfire and the cylinder are  close together you may need to rule out a mechanical condition by doing a cylinder leak down test.  This can just be one cause , another cause is vacuum leak especially at the throttle body at or near the MAP sensor this is where a vacuum leak are likely to occur and cause cylinder 2 and 3 to misfire.and give a lean code condition.