I have a 2000 Excursion, with about 199k miles on it, 2WD, Automatic. Recently started running rough, but only when in gear. Seems to occur more when in reverse. But, within the last few days, i have noticed it starting to run rough while in park. You can rev up the engine and let it settle, and it will sound fine, run fine. Don't see any issues while driving it, between the engine or the trans.

I am leaning towards the injectors being the issue, but not 100%. The engine also started sounding sloppy when shutting off, like it wouldn't stop rotation right when you kill it. It doesn't stay running, but has that extra clank, like it takes longer to stop. (Hard to describe it) I just put some cleaner in it yesterday, and i was going to see if that helps any. Just wondering if anyone else had any ideas of what it may be before i tear it down.

 

There are numerous things that can cause the symptoms you have described. Before attempting to diagnose such issues some data is necessary to determine what road we take.

If it's at all possible, we will need the following data when the Truck is Cranking, Cold, and at OT:

Sensor Monitoring

Tools: OBD-II On-Board Diagnostics, Phase 2 Vehicle Media Communications Unit (Scanner)

1. Select the parameters indicated from the Scan Tool parameter list and monitor while cranking engine.

Data List Monitoring Parameter:

Vehicle Power (V-PWR) 10.5 VDC Minimum.

RPM 100 - 150 RPM Minimum (0 - CMP Suspect)

Injector Control Pressure (ICP) 500 PSI or 3.4 MPAM Minimum

Injector Control Pressure Voltage (ICPv) Key On Engine Off (KOEO) Spec: 0.20v - 0.30v

Injector Control Pressure Duty Cycle (ICP %) Spec: 10%-12% at idle, engine at 140F or > / NTE 20% while Cranking / 65% is closed (IPR Suspect)

Fuel-Pulse-With (FPW): 1 MS - 6 MS (<1 / >6 IDM Suspect)

*V-PWR - If indicating a low voltage condition, check battery voltage, charging system or power and ground circuits to the PCM.

Exhaust Back Pressure (PSIG)

Manifold Absolute Pressure (ATM)

Mass Fuel Desired (MFD) (mg)

Volume Fuel Desired (VFD) (Cubic mm)

2. ICP - A minimum of 500 PSI (3.4 mPa) is required before the injectors are enabled. No or low oil in the reservoir, system leakage, injector O-Rings, or faulty IPR could cause pressure loss. You can disconnect it from the wiring harness. The PCM is programed to use a Delta of 700 psig. Driving the vehicle while disconnected is not recommended.

Note: If no RPM signal is received, IPR duty cycle will default to 14%

3. FUEL PW - Even though a 1 to 6 mS FUEL PW is shown, it’s possible the IDM did not receive the signal due to a CI or FDCS circuit fault or internal IDM failure.

Hope this helps,