Engine/Transmission (1998.5 - 2002) Is my APPS going??????

[BRI7070]

Over the past few days I have noticed that there is something not quite right with my truck.



Occasionally when starting from a stop using medium to light pedal the motor would start to rev ,about 1/2 a second, then I would feel a bog for about 1/2 second then it would act normal. It seems to be in one particular position in the pedal and will not happen all the time.



Any Ideas. I have used the search feature and did not find what I am looking for.



Thank you

 

[Alan Reagan]

Could be the APPS or the Camshaft Position Sensor.



First you could do the on-off-on-off-on and see if any error codes come up in the odometer.



If no error codes, you can recalibrate the APPS by disconnecting the batteries for 40 minutes. Then reconnect. Switch to on (don't start). Slowly depress accelerator pedal to floor and slowly release. Turn off switch.



If that doesn't solve the problem, I would start thinking CPS (on your's it's the Camshaft Position Sensor).

 

[Agades]

I have been told that the APPS calibration is a one shot deal



once its been calibrated you cant do it again



is this true?

I dont know

 

[JR2]

Your not really calibrating the APPS you are calibrating the APPS to the ECM. I believe that pulling the neg cables off the battery for about 40 minutes causes the loss of all the calibrations in the ECM... so in theory you should be able to do it as many times as you want.





Its also good to do it over whenever you have the negative terms pulled off the batts for over 40 minutes. Like after installing injectors or whatever.





JR2

 

[Alan Reagan]

Yeah, You can do this all you want. It's the ECM cal being done.

 

[Agades]

if the camshaft sensor is going, wont the tach bounce around a lot ?

 

[Alan Reagan]

Not necessarily. Sometimes they have these symptoms. This could also be a symptom of a VP-44.

 

[BRI7070]

I have checked for codes with the key and nothing has shown up. I also preform the APPS cal about every other month. I will try the APPS cal again.



If my Cam sensor is going out what would be the indicators? How do I trouble shoot this?

I have always had tach bounce of 50-100 rpm.

 

[kaffine krazed]

Doesn't the ECM use nonvolatile memory so disconnecting the batteries doesn't clear it? I know I've had the batteries disconnected overnight and the codes don't clear from the ECM.