2001 Ram 2500 6spd (g56). I have been having this problem where when it's really hot out and the truck has warmed up for a few hours I get a bucking when hitting the accelerator (harder you push the go pedal the worse it gets). It's a jerking forward release jerk forward release. I noticed today they when I push the clutch in it wont rev past 3K and sounds like it's underwater.

Before I thought it was an ignition problem because it would buck at 3K and if you don't WOT the pedal it would be very faint (now it's a little more pronounced even when not at WOT but not as bad as when at WOT). So I relieved the ignition coil and TPS with NTK. Tune up was done with copper plugs and wires about 8,000 miles ago and I no longer have the Plenum.

I think it's the cat so I will check that here in a bit when I get home. If it is the cat here is my plan (let me know what you think). I'm going to cut the exhaust a little after the post cat O2 and gut the cat start the truck up and let it throw the pieces out. Then get a piece of pipe that goes into the car and over the other exhaust piece and use a banjo clamp.

 

You can cut a window into the cat(on the side of the cat, peel back the metal to reveal the inside guts of the cat), pull the guts out and re-weld the window.

 

That would be a weird cat issues if it only shows up when it's really hot. Hall effect sensors like the CPS tend to get problems at higher temps before failing completely.

 

Thought about that but this exhaust is on its last leg it will burn right through it

 

Thought about that but my scope shows it to be fine

 

Yeah, up there in parts of PA, metal can tend to get thin over the years of exposure to road salt... If its not too thin, you can cut out an opening on the cat at the thin area and weld a plate over it.

 

Ok. Anything suspicious in the live data when it's acting up ? MAP, temp, fuel trim, readings. If the cat isn't working it should not cause issues except for possibly setting the efficiency code (although I think these old PCMs are pretty lenient). If it doesn't flow the inlet side is much hotter than the exhaust side, and the pressure on the inlet side is high (either drill a hole and use some brake line as a pressure gauge port or remove the upstream O2 and measure there). Up to 3 psi is normal.

 

Nothing that I seen. Everything looked normal to my eyes. Fuel trims look to be as tad high but the exhaust also has a lot of leaks so it is probably thinking it's to rich. I do the old rattle test and the cat passed I'll check the temps tomorrow after coming back from my NY trip

 

What kind of fuel pressure?
Do you have a M1?

 

Hughes AirGap