Engine/Transmission (1998.5 - 2002) Limp Mode

[sp_longhorn]

Ok guys i need some help with my neighbors truck. 99 model automatic with 70k on it. When truck has couple hours driving time on it while pulling a load the truck acts like the throttle stays right around your current rpm but a very noticable change in torque and/or boost. The throttle becomes unresponsive either wide open or completely letting off. Truck will return to responding to the throttle after you completely let off for few seconds or put in neutral and back to drive. My fathers done something similiar to this with his 02 manual changed vp44 and problem fixed. Do you think this is the problem here or cam/crankshaft sensor??? Thanks

 

[JLandry]

Has anyone checked for trouble codes using a code scanner? That might be helpful to narrow things down a bit.



It sounds like it could the be the APPS (Accelerator Pedal Position Sensor) is failing. Do some searching here on the forum on the words APPS and TPS (Throttle Position Sensor) for a wealth of info.



John L.

 

[Bob Cochran]

I vote APPS first before Injector pump codes would help.

 

[magaliasram]

Put a noise filter on that puppy and solve your problems.

 

[sp_longhorn]

Checked codes not showing any.

 

[Bob Cochran]

If bad APPS more than likely would be setting codes.

 

[blacksheepdiesel]

It is most likely the injection starting to go south.

Check for codes. My VP44 and APPS have both been bad at different times and never set any codes.

You can swap an APPS from a buddy's truck with no known symptoms and see if that cures it.

Godspeed,
Trent

 

[turbo torque]

I recently had APPS go bad and, the only code set was for the MAP Cleaned map and still no good.

I talked with Timbo (great guy), I got an APPS from him at a great price and , all is fine now.



best of luck