I have recently taken my 2002 Ford F-250 on a 200 mile trip. The highways taken had hills, leading the engine to seemingly struggle in some uphill spots. When trying to accelerate uphill, the engine seemed to hesitate and shake a bit, making me think it was initially an electrical spark issue. But, I found that after it downshifted, the engine was performing normally. I am wondering if the gear ratio is off and needs to be updated a bit. The four speed transmission may struggle to downshift quicker at higher speeds. Another problem, and potentially a more concerning one, is poor engine idling when in gear. When the engine is fully warmed up, I sometimes worry the truck will stall out since the idle power is fluctuating. It should be noted that it performs much better when the engine is colder for whatever reason. This happened once before the plugs were changed and is not consistent when driving. Any thoughts on this? Thoughts and feedback would be much appreciated. **It should be noted that all spark plugs and coils were recently changed and this should not be the issue. The fuel pump is most likely aged in case this appears to be a fuel issue.

Thanks,

Andrew