leeboy

Since about July , i remeber taking off slowly and as it started to pick , it felt like my foot slipped off the pedal . So, i looked down to check and it never. Never thought much about it. Last week , i was at a stop sign kinda going up hill , and as i started to creep up the hill, it did it again. Kinda like , i lifted my foot off the pedal slowly and then went back to where it was. I still have 14lbs of pressure on my fuel pump gauge.So, i went and bought a filter and changed it. Today, i was driving about 40mph , ( i have a automatic) foot steady on the accelerator since i was in morning traffic. And it started again. Just like i slowly lifted my foot off and pushed it right back down , did it a few times . Then the rest of the day was fine. I can stomp on it and it has full power with out a hiccup. Starting to scare me since i do work 2 hours out of town sometimes. No "check engine light is on and its not like when the crank sensor goes , just like im taking my foot off and putting it right back down. Any tests i can do or ideas what could be going?

Tallguy67

Leeboy,
First things first, before we start throwing parts around, do you have access to a code scanner? The turn key 3 times trick only works on a few years models of our trucks and I don't think a 99 is one of those years. Over here in Alberta most of the parts stores have code readers that they will let you borrow to use in the parking lot.
Next thing I would check would be your APPS. You have a pretty high post count so I assume you know what an APPS is and how to use search to find the APPS test and calibrate procedures on this board. If not, say so and one of us will help you find the procedure.
If you get past there and the problems are still occurring, read the following information before you assume your VP44 is on its way south, these are some of the best VP44 diagnostic procedures around.

BTW - you can often have codes without the CEL coming on. There are 2 classes of codes (haven't read FSM in a while so I cannot remember the name of the 2 classes) but essentially there are soft error codes that are for minor problems and they don't make the CEL come on. Then there are hard codes that immediately turn on the CEL as soon as there is even one hard code in memory. Soft and hard codes probably aren't the right terms but I don't have my FSM here to look up the proper terms.

http://www.bluechipdiesel.com/vp44diagnostichelp.html

leeboy

thanks for the info, i remember a technique on resetting the APPS when my tranny was surging a few years ago. I will see if i can search that out and find it again.

pjtaddeo

Gents,
First post here, but not the first time finding help. I just recently have been experiencing a similar problem the last few weeks or so. I've got a similar setup as Leeboy, 2001 w/ FASS DDRP still showing about 18psi. I also was messing around with the APPS sensor a few years ago, so will get familiar with it again. I'm going to try a few of Tallguy's suggestions, but I'd be curious to know if you find a solution.
Pete

SIXSLUG

You can check codes on an 01 with the key trick.

Codes scan and show ECM and PCM codes and p-done when finished.

ECM Engine Control Module pertains to the engine

PCM Powertrain Control Module everything else.

pjtaddeo

First thing I did, read Blue Chip's article on VP44's. I also remembered that I replaced the APPS about 2 years ago for possible transmissions issues (I ended up needing a rebuild, about 155k miles at the time). Second thing was check codes, both with a OBD reader and the key turn method.....no codes. Third thing, just finished replacing the fuel filter as mentioned in Blue Chip's article as one of the first things to do with my symptoms, and it was about due anyway, 13k since I last changed it. So, I'll have to give it a few weeks and see if the problems returns.