First post in this section but not new to FTE. But I need some help. I bought an 03 Ranger XLT 4x4 with a manual. It had okay pickup but I wanted a bit more because I'll be towing a trailer with bikes. So, I changed the oil and filter, got new tires all 4 the same size (it came with 3 235/70-16 and 1 245/75-16), replaced the air and fuel filters, cleaned the MAS and added a flash programmer (towing mode).

The power is there from first, second and third gears. Fourth, it starts to feel weak but will still accelerate. In fifth, if there's an incline, the rpm's start to drop to the point that I have to downshift. There are no engine codes either. I've done the NAS sensor cleaning with the ground at the battery disconnected for over 40 minutes to clear the pcm. I thought for sure there would be a code but nothing. I know the engine is a 4.0 V6 and not a 7.3 Powerstroke but come on, it can't be that weak. I didn't change the plugs and wires yet.

Any insight and help is greatly appreciated.

Jim.

 

fifth gear is a .75 to 1 overdrive and I suspect that your Colorado inclines are at least similar to Montana inclines - so I'm going to suggest that it's probably normal to have to downshift it in those situations after all you've only gat a maximum of 240 ft/lbs of torque and that's at 33-3400 rpm.

 

You mean I don't have the same torque as the Powerstroke? This is going to be a bigger adjustment than I thought. Thanks for pointing that out.

Anyone put a supercharger on a 4.0?

Jim.

 

..............Elevation plays a significant role in the power of your truck . You're going to loose about 4% of the rated torque for every 1000 feet of elevation above sea level . At , 10,000 feet msl your power will have been cut by close to 40 % . , rb

 

Thanks for your inputs. I'm at 7500 feet.

Jim.