wffokker

Got a 1998 2500HD with close to 190K

I have been messing with it for the last 4 months trying to get it to run right, but it is getting worse every week and am down to almost not being able to get where i need to go with a loaded trailer, and i need this thing for work.

It started out with the truck holding back when putting it to the floor, if i let of a bit it would shift and take of like it should but if i didn't let up it would just hold back and kinda stutter
Afew weeks later it would hold back at times at half throttleand then it would run great for a while and go back to running like crap, i have been trying to find a pattern but there doesn't seem to be one, weather, load, fuel, etc

Last spring it got a cap, rotor, crank sensor, couple weeks ago new plugs, wires. Cats are now also clean.... just put in a new o2 sensormass airflow and AIT sensor this week

After cleaning the cats it ran a bit better when it seem to feel right, but the times that it did not feel right it didn't make a difference

Sorry it forgot to mention it has 5.7 with 4L80E behind it 4wh, ext cab long bed

Now it seems to flood out if i give it more than 1/4 throttle if i give it just a bit of throttle it will pull heavy trailer up to 40 mile an hour but takes a few miles to get there, in 4 low it acts the same.

The amount of throttle it will accept seems to get less and less by the day

Bank one sensor one o2 is new but has throw a code twice since i changed it few days back. CEL will be off and then truck will shutter and cel comes on showing bank one sensor one low voltage i believe.
To me it seems like it floods out when i give it more throttle than where is seems to be happy at but fuel mileage has been about the same as before.

Anybody have any ideas?? Gone hook up a tech II tomorow and run a movie to see if we can find it but the guy with the tech II has looked at it before and doesn't seem to know what is wrong with it so far either

Your help is greatly appreciated.