2000 5.3l yukon wont go up steep inclines

[Mattsyukon]

My 2000 Yukon won't go up steep grades. I was trying to go up my in laws driveway the other day and it got steep and the yukon came to a stop while I had the gas pedal to the floor. When I got back to level ground every stop light I would stop at it would idle very roughly. I can put it in neutral and park and it idles fine. Does fine driving on level ground but very steep grades at low speed it will not go. Checked the fuel rail its 50psi at idle 60 psi if I power brake it to try and simulate a hill. Tested the throttle position sensor and it's fine I also have no cel. Any suggestions?

 

[wjburken]

My 2000 Yukon won't go up steep grades. I was trying to go up my in laws driveway the other day and it got steep and the yukon came to a stop while I had the gas pedal to the floor. When I got back to level ground every stop light I would stop at it would idle very roughly. I can put it in neutral and park and it idles fine. Does fine driving on level ground but very steep grades at low speed it will not go. Checked the fuel rail its 50psi at idle 60 psi if I power brake it to try and simulate a hill. Tested the throttle position sensor and it's fine I also have no cel. Any suggestions?

Welcome to the forum.

Does the motor stall out and die or does the motor run but you just don’t get any power to the wheels?

 

[Fless]

Yes, welcome to TYF. Have you checked the transmission fluid level per the owner's manual?

 

[OR VietVet]

Might also want to check for clogged catalytic converters. Mileage on the rig and any recent work?

 

[Scottydoggs]

if it fights to run at idle in gear, or worse in reverse the torque converter could be shot.

 

[Mattsyukon]

Welcome to the forum.

Does the motor stall out and die or does the motor run but you just don’t get any power to the wheels?

It runs but not over 800 rpms and no power to the wheels. It doesnt miss or anything while I'm on the gas on the hill just when I let off it stumbles bad but doesnt stall out.

 

[Mattsyukon]

Yes, welcome to TYF. Have you checked the transmission fluid level per the owner's manual?

No but I will shortly.

 

[Mattsyukon]

Might also want to check for clogged catalytic converters. Mileage on the rig and any recent work?

I did take it to the shop and they flow tested the cats for me and they said they were good. I am at 268000 miles

 

[Mattsyukon]

if it fights to run at idle in gear, or worse in reverse the torque converter could be shot.

That's sorta where I'm thinking but wasnt 100% it would act like that.

 

[Mattsyukon]

if it fights to run at idle in gear, or worse in reverse the torque converter could be shot.

It does shake the motor pretty bad after I'm stopped at a light for more than 10 to 15 seconds. I'm leaning more towards the torque convertor now that it's starting to add all up.