2002HD 8.1 rough acceleration

truck has 54k, love the truck - have had 0 problems. about 3 wks ago it started to miss fire on acceleration over 30mph and above. Can't even accelerate over 60 or on any hill or incline. thought it was bad fuel, nope. it does have the original fuel filter. truck is at the dealer as of this posting. Any ideas??

Space in cyber space to go through all the stuff it could be.

Is the 8.1 a disel?

If so you might have a lot of water in the fuel????

The 8.1 is gas. got it back for the dealer yesterday, he flushed the fuel system (claimed that was the problem, nope - wasted $130) and changed fuel filter. Improved slightly. Condition still exists. Other suggestions are the throttle position sensor and/or the oxy sensor. Bringing back on Mon. Will update

Then it is not a sensor or anything like that. When a sensor fails the engine goes on. If the oxygen fails the engine light goes on.

But like when you are getting no spark to the spark plugs you get no engine codes.

They do not know what they are doing.

I am wondering if it is the fuel pressure reg. Seems to go out a lot on these trucks.

They are sucking you dry.,

If you bring it in on Monday that if they do not fix the problem then you should not have to pay for service that does not repair the vehicle.
That is just fair.

One thing really worries about this. They told you what was wrong and it did not fix it. Well did they even finish 8 grade ? I smell a skam.

Can you do a fuel pressure check?????
You can get an gauge at Autozone or O'reily.

Have you unplugged the battery for an hour and start it up?
My wifes van freaks out from summer to fall. I always have to run fuel injector (PRO CLEAN) throught the fuel rail and disconnect the battery.

1.Take the PCV valve out and clean it with wd-40.
2. Get some throttle body cleaner and with the engine running spray it all over the butterfly of the trottle body.

Keep me up posted.

Problem solved - spark plug wire was rubbing aganist the steering shaft coupling clamp. Only grounded when the shaft was in the exact position and when the engine torqued. New wires. All is good.