GreenMonkey
Newbie
- Joined
- Nov 10, 2011
- Messages
- 36
- Reaction score
- 43
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.