Loss of power

Where is the fuel filter located

I was leaving for a trip and vehicle lost power trying to go up an hill/incline. When I stopped and turned off to look under the hood and got back on road. It ran fine until another hill. I came back home instead of finishing the trip. When I went to fuel up I check the check mileage. I usually get about 20 MPG, this 100 mile trip I only got 6 MPG. No engine lights have ever come on and had mechanic check for codes. His opinion is that it is the transmission. 1,300 miles ago the dealer changed and cleaned AT. Any help to find something else to check?

Can a leak around the gear box also cause the feel in the rev; thus in acceleration peddel. There is a leak of transmission oil at the left shaft joint and Also the 4wd attachment.
Today we used these autofix machines on it and most of the detected faults were Air related

I found out dat the purge Control valve was not properly connected.
Can the viscosity of the Engine oil affect the performance of Engine. Relating to speed and sound

I use 5W40 but changed it to 15W40. Any warnings or worrys?

I had the engine light come on, had it code checked came back as p0120 asn p0121. Vehicle ran great, started fine idled fine, now suddenly has no power, or acceleration. I changed the tps, and the engine light went off, but still has no power or acceleration What seems to be the problem?

Over site. I recently got to know of it

I will try that. I also switched back the old tps, and loosened the throttle cable, it has given me some power back, but not much. I can get to speeds of 60-70 it just takes a while and any slight incline is a struggle, but it does respond to needing more fuel. I will update once I cleaned the throttle plate. Thank you.

The plate is clean, but still no power. Regarding the fuel pressure I am not sure, nor do have the knowledge to do it. I did try to pull any codes from it, but as the light is off no codes were found. Swapped back the old tps, and still same thing no power, and does not really respond to pushing the throttle.

This morning on the way to work, when my car got up to about 40 MPH on the highway, it seemed to "bog" down and lose power. All my fluids are proper levels and colors, my belt is in good condition and is working properly, and no indicator lights have come on in my dash. I am afraid it may be an issue with my transmission?

Just had my car repaired for the same problem. 94,000 miles 2001 santa fe. Mine seemed to be a transmission problem, not up shifting into higher gears caused by catalytic converter located under front seats. Have that one checked for blockage and if so replace it. No check engine light displayed.