HELP 00 K2500 CCSB 5.7 is A GUTLESS gas guzzler

[TGS00]

Recently purchased a 2000 CCSB with the 5.7 with 200,000mi on it. Right after I got it I did the cap, rotor, plugs, wires, pcv, cleaned the maf sensor, volant cai, it also has a helix power tower, oil change. It's got 3.73 gears and a 4L80 in it running stock tires. It was still a gutless fuel devouring pig. Just the other day I cut the cats out of it (which were plugged right off) and it didn't help one bit. There's no codes on it. I was driving on the highway yesterday and was going up a hill, put my foot into it and the thing didn't increase in speed at all . I had a 98 ecsb that would blow the doors off this thing and triple the fuel mileage it's getting. I realize it a heavier truck but come on! Really not sure what to do here guys any help at all is truly appreciated.

 

[montess85]

Could just be tired. Also did your other truck have a 4l60?

 

[dowsewashere]

Well it has 200,000 miles on it. And its a truck. Like above it be a tired, worn out pig and the 4l80e is going to limit you as its a heavy duty transmission for towing. What about your fueling system? If it has 200k and an original fuel pump and filter it could just be on its way out.

 

[IOWNJUNK]

At 200k I'd be happy it cranks and goes down the road. Might be time for a rebuild. Do a compression test and see what your numbers are. Probably all low.

 

[phule]

What are you getting for mileage? My 99 c2500 5.7 4l80e averages about 13 mpg. Wich is marginally worse then my crown vic at 17.

Adam

 

[great white]

Recently purchased a 2000 CCSB with the 5.7 with 200,000mi on it. Right after I got it I did the cap, rotor, plugs, wires, pcv, cleaned the maf sensor, volant cai, it also has a helix power tower, oil change. It's got 3.73 gears and a 4L80 in it running stock tires. It was still a gutless fuel devouring pig. Just the other day I cut the cats out of it (which were plugged right off) and it didn't help one bit. There's no codes on it. I was driving on the highway yesterday and was going up a hill, put my foot into it and the thing didn't increase in speed at all . I had a 98 ecsb that would blow the doors off this thing and triple the fuel mileage it's getting. I realize it a heavier truck but come on! Really not sure what to do here guys any help at all is truly appreciated.

Triple?

Really?

So you're only getting 5 MPG right now?

 

[bluex]

My truck with 271k miles an 305/70/17 with 3.73 gears gets 13. before the tires it got almost 17 still with over 200k miles on the oe drivretrain...

 

[michael hurd]

Yes, there seems to be a number of 5-8 mpg trucks on here...

It's pretty much impossible to calculate mileage from one day of driving after removing plugged convertors. Realize that in the winter you can pretty much halve your fuel economy with winter fuel, extended warm up periods, and so on. Cold oils do not help the situation.

Take the power tower off and the aftermarket intake, and re-install the factory stuff. Pull the throttle body and clean it thoroughly. Check the throttle position sensor with an analog meter to make sure there are no dead spots, and if in doubt change it.

With this high a mileage, there could be many, many problems stacking up against getting mileage out of it. Since you recently bought it I would take it in for an alignment to make sure that it is within spec.

 

[tomb]

Compression test? I also have a 00 5.7L k2500, same hardware & gears. 15 city and 17 hwy. (65k miles) I think you have a problem.

 

[Crash]

I had a 00 CCSB 5.7 with 265/75R16 and no mater how I drove the best it would do on the hwy was 15mpg.