Engine/Transmission (1998.5 - 2002) Map Sensor????

[MTPhillips]

My truck is losing power every once in a while. When I'm driving down the road it will seem to lose power for just a few seconds then spool back up and be fine. My fuel mileage is bad... . about 13 to 15mpg..... Another thing it's doing... . about 55 mph to 60 mph..... it feels like the truck is surging. Or maybe shuttering would be a better word to describe it. Any help would be appreciated!!!!! I've also added a Fass system recently. Fuel pressure is great about 13 to 15psi.

 

[barbwire]

Is the fuel pressure you stated pre, or post filter? injection pump failure??? I guess I am interested in the replies you get also

 

[smokejunkie]

Have you tried changing your fuel filter. Sometimes little things that get overlooked can be the answer.

 

[dieselshu]

MT, sounds like the TPS Throttle position sensor, but I have read other threads that the dealer replaced the VP-44 and the same or similiar problem went away. Do a search on TPS and you can read the threads I am talking about. Goodluck and hopefully it's not the VP44.



Dave

 

[TURBOs4LIFE]

YES! I am getting that same surge/hesitation but this was soon after installing the Hot Rod VP-44. Mine is when I am just barley on the acclerator and under 5 psi of boost and is a little worse when its cold. Truck still runs great otherwise and I have read and know that the HR VP-44 acts a little different (When put into gear and coming to a stop it sounds like its caming like a gasser!) I need to know if this slight surge normal or if I have something going bad?

 

[cerberusiam]

MTPhillips, the surging at 55 to 60 sounds like the converter hunting for lock. Do a search and you should get a bunch of info and fixes.



The power drop, or dead pedal, could be a VP failing. There are other things that could cause it but generally it is a failure in the pump circuit. Add on boxes and in some cases tuners can accentuate to the point it is noticeable.



Have you checked for codes to see if there are any?



Try the easy things first, check your batteries and make sure they are both good, clean & grease & reset the connections to the ECM, APPS, etc, dump the computer and reset the APPS and see if that helps or changes the problem.



FWIW, almost all the problems like this have eventually ended up in a VP replacement. Some times it can take weeks or months to get it to fail enough for codes to show or dealer to replicate. Took me 2 weeks to get the 99 to fail hard enough to throw the codes to verify it was the pump. If you have access to a trailer load it down, find some hills, adn drive the snot out of it and see what happens. Thats how we finally got the codes to show. Good luck.

 

[MTPhillips]

Thanks for all the input..... I'll try some of the simple things first. I have no codes yet, but how do you dump the computer? I think I know how to reset the APPS... . do you disconnect the batteries for about 30 min then hook them back and turn the key on, but don't start... . and slowly push the accelerator to the floor and back up slowly... . three times? If that isn't right let me know.



By the way my batteries are good and the connections are great..... not a problem there. Oh yeah my fuel pressure reading is post filter. The FASS is only about 2 months old..... could a filter be dirty that quick?

 

[cerberusiam]

The key on-off 3 then leave it on should dump the codes in the odometer read out. I usually disconnect the batteries then turn the key on to completely discharge everything. Correct on the APPS rest, some say once is enough and some say 3 is correct. Done both and couldn't telt the difference. Can you set your programmer back to stock? See if that changes the problem.

 

[MTPhillips]

I'll give it a try... ... thanks.