Code p0122 and shuddering

[GreenMonkey]

Well, I’m back with another issue I’m struggling through. I’ve got a 1998 k3500 4x4 with 7.4 and nv4500. Recently, my truck started shuddering in 3rd, 4th, and 5th gear when accelerating. Not noticeable in 1st and 2nd. It does this once it warms up, but not when it’s cold. My scan tool says it’s a p0122 code and also gives me an 02S, HTR, and EGR undreadable and not ready for emissions code. I tested the voltages and everything checked out, but the truck still shuddered. I went ahead and replaced the TPS since it was 25 years old with a Standard Ignition TPS. I back probed all 3 wires with the new TPS just to verify. I was getting 5.00 volts on the power wire, 0.5(idle) to 4.53(full throttle) on the signal wire, and 12 on the ground. It increased and decreased steadily throughout the range. Then I checked the signal wire at the ECM and it was matching the voltage at the TPS output. However, the shudder and jerking are still there just as before. Also, all my fuses look good. Any ideas on what to do next? Is it possible a bad 02 sensor is causing this, or is the p0122 code causing the 02 and egr codes? Thanks in advance for any help and suggestions.

 

[Kevin Callahan]

Have you found out what was causing it? I have a 97 tahoe automatic. with almost identical issues. It has me stumped. Everything seems to test fine. I'm starting to lean toward the torque converter but if you're having the same problem with a 5 speed then I need to look into something else

 

[GoToGuy]

So the 98 OE service manuals are available for FREE pdf download. Use the search bar at top " service manuals " . The posted link is in one of the paragraphs.
In the fuel and emissions section breaks down the DTC codes. Defining what is causing the codes.
That is what I would do , you have codes, get better malfunction description, then confirm what's happening, then what to repair. Don't just guess and change parts, confirm what's broken , then repair.
There are good charts in their for diagnostic checks.

 

[Kevin Callahan]

So the 98 OE service manuals are available for FREE pdf download. Use the search bar at top " service manuals " . The posted link is in one of the paragraphs.
In the fuel and emissions section breaks down the DTC codes. Defining what is causing the codes.
That is what I would do , you have codes, get better malfunction description, then confirm what's happening, then what to repair. Don't just guess and change parts, confirm what's broken , then repair.
There are good charts in their for diagnostic checks.

Not to hijack green monkeys post but that's the worst part of my issue with my 97 is it has zero codes

 

[GreenMonkey]

Kevin, I’ve had some things come up in the last month and have not figured out the issue. I’ll look at the service manuals soon and see if I can find the problem. If so, I’ll post back with a solution.

GoToGuy, thanks for the suggestion. I’m having issues downloading those files, but have used them in the past successfully.

 

[Kevin Callahan]

Kevin, I’ve had some things come up in the last month and have not figured out the issue. I’ll look at the service manuals soon and see if I can find the problem. If so, I’ll post back with a solution.

GoToGuy, thanks for the suggestion. I’m having issues downloading those files, but have used them in the past successfully.

I ordered a better scan tool than what I had so I can watch more live data while driving. If I come up with anything that way I'll let you know

 

[GreenMonkey]

I ordered a better scan tool than what I had so I can watch more live data while driving. If I come up with anything that way I'll let you know

Thanks man. Got a buddy with a snap on scan tool that we’re gonna use this week to get some live data as well. Hopefully we can get this problem worked out.