Hi all,
I have a 01 Pathfinder with 170k miles that is struggling to accelerate, especially going uphill or at highway passing speeds. It has been manageable but last week I was driving up to the mountains and couldn't get it over 55 mph on the highway with a 5% grade. I didn't have it floored and the engine was at 3k rpm, I gave it more gas and got no response in rpms or speed, finally I just about floored it and it downshifted to ~4.5k rpms but still no change in speed.

I have had two P1145 codes over the past year. Both times I replaced the cam shaft position sensor and the code went away. No noticeable change in acceleration when the codes came on or off. Could the sensors be sending bad signals without the CEL coming on?

I checked the air filter, looks clean. Replaced the fuel filter, no change. Any recommendations on what to inspect or replace next?

Thanks in advance!

Sounds a lot like my old '91 Pathfinder. The engine was well maintained but after 235K miles and many battle scars, its get up and go got up and went when it came to hill country. Mine was manual so I could deal with downshifting well enough to keep the engine revved high enough even though I would only be able to crawl uphill. Otherwise, it was just fine driving without any significant grade but it didn't have much punch to merge quickly onto a freeway. All my cylinder compression values were at the very bottom end and below specifications but I never had the opportunity to get the piston rings replaced and cylinders honed before some kid running a red light t-boned me and put my old '91 out of its misery. Checking your cylinder compression values to see where your at is all that comes to mind.