Weird thing happened . I was just coming home from my girlfriends house(11:00 pm), truck was running fine, i pulled over on the side of the road because an ambulance had its lights on was coming towards me. Ambulance passed so i went to come back onto the road and started to let my clutch out when my rpms just started bouncing from like 600rpm to 800rpm. The needle would just bounce back and forth. I gave it throttle and nothing happened, no response, just kept bouncing. Tried letting clutch out agian and that just made the truck lunge as the rpms bounced. I switched to my high idle postion on my chip and it seemed to keep it steady at 1000 rpm and i used that to go 3 more blocks down the road, then my rpms start bouncing agian and i couldn't go. Shut the truck off and played under the hood a bit with some connections. Jumped back in and it started up fine and ran perfect the rest of the way home.

Any idea what the heck was goin on????? I did wash the motor two days ago, and used an air hose to blow most of the water off, then let it air dry. I took the truck for a drive earlier today, and it had ran fine then. Any idea what acted up tonight??? I assumed no water got in anything because it ran fine earlier. Maybe a cps issue??? Thanks guys.

 

No throttle response, engine idles only, DTC's P0220 or P0221; Vehicle jerks in parking lots, especially manual transmission:

Idle Validation Switch.

The IVS tells the PCM that the accelerator pedal has returned to the idle position. Even if the pedal is fully depressed, if the IVS remains off, the engine will only idle. Watching the IVS and AP data stream, the IVS should switch on below 1.41 volts according to Ford. Navistar spec is 0.2-0.3 volts above base AP voltage. If the PCM sees the Accelerator Pedal sensor voltage increase with out the IVS switching on, it may set a code. The IVS and AP sensor cannot be replaced without replacing the entire pedal assembly. If the IVS switches on at too high of a AP voltage, it can cause the truck to buck at low speeds as the IVS cycles on and off as the driver tries to control his speed. The only way to correct this is to first loosen and turn the AP sensor to reach the lowest possible voltage reading on the scan tool and retighten. Then bend the IVS stop to adjust the on/off point to 0.2-0.3 volts above the base AP voltage reading. Note: There have been cases of lack of throttle response and the above codes which were caused by the PCM not recognizing the IVS "on" signal. Replacing the PCM corrected the problem.

 

Thanks Wlihntr,

That pretty much describes it. The IVS cycling would explain the bucking and bouncing rpm. I'll have to try adjusting the IVS and AP sensor and see if it ever returns. Thanks agian.