Truck randomly jumps to 2500 rpms

[95Yukon]

Hey guys i got a problem with my truck and im hoping someone here can help me. Today i was letting the truck idle and out of nowhere the truck started to idle up on its own. It started out just jumping to 1000 rpms and then started running WOT without me even touching the pedal. When this happened i shut the truck off and let it sit for a while. it seems fine for now but it did this to me about a month ago too. It has a new i/p, lift pump, fuel filter, pmd and heatsync, new air filter, and new APP sensor. Thanks for any help

[trukdoc]

...check wiring at tps{foot feed assem.}they do wierd things when they start to go out...may or may not set code but would'nt hurt to check historic codes...

[95Yukon]

Last time this happened I checked the codes it gave me and im not kidding when i say it was throwing every code imaginable out. i cleared the codes and the only ones that came back was for my low vaccum. Do u really think the TPS could already be going up? Its only 2 months old

[vmac4]

I would be checking the wiring itself for chaffing and corrosion.look at the
connector pins and shells for damage.Another possible source is the ecm,or
pmd.Mine did what you described when my pmd went out,And it would set
a accelerator pedal code,changed it and cured that.

[trukdoc]

...multiple codes,related or not,is probably a bad ground or a shorted or "rubbed" wire in harness related to tps{foot feed assembly}back probe wires at connector to pedal.will have batt.voltage feed ,ground and signal wire.....also as last post said check pins & sockets for loose or corroded pins...good luck

[trukdoc]

...check ALL cab-frame-engine grounds..alot of electronic related problems are cured by finding and fixing a broken or loose ground..

[95Yukon]

well i was driving the truck today and it started acting up again, when i checked my gauges i noticed that my voltage was rather low (9-11v) do yu guys think my low voltage problem could be the cause??? Im hoping it is so that i can justify ordering a bigger alternator.

[Stumped]

I would bet the sandwich style batt term on drvers side has corrosion between the 2 halves.Mine went from 11-12 to 14 by cleaning them.

[markus999]

Assuming (but you know what they say about assuming) that you are still getting all kinds of codes your original dash volt meter is erratic and it acts up intermittently I would check ground and power circuits. To really understand what is going on we need more information. Codes, does it occur shifting into or out of gear, over bumps/smooth roads, does the volt meter always drop when the problem occurs? Can you make it do it? You said that you were at idle. Was that in gear?

Saying all of this my truck will do something like this for no more than a second (at least for the past 4 months) and maybe once every 2 weeks. It seems only after I shift it into gear (forward or reverse) and never has done it while at road speed. It always sets one of the TPS faults. I've checked grounds and power circuits. I would replace the TPS but its not that big of a problem at this point.

Hope the info helps.

Mark

[95Yukon]

my voltage has been low like i said it stays around 9-12v even at WOT with all accesaries on. This is my second alternator and im wondering if sumthing is up wit it causin the problem

[grancito]

Get a multimeter, check the voltage in various places, batteries first. If the voltage at the batteries with engine running is really 12 volts, they will go flat.

[trukdoc]

...readin over posts again and got to thinkin{who da thought}eyeball posi cables have seen cables with a "hard or stiff" place or a spot that looks pregnant{swoll up}this is corrosion in side of casing happens on old cables causes hi resistance in chg circuit{lo volt flo}also makes fluctuating volt to computors...dont start shakin your heads thinkin the fatboys lost it...have seen this over the years in the fleet and allways after lo volt or lo chg snivel...