a buddy of mine bought my old truck (00 silverado) from me about a year and a half ago. in the last week hes been having electrical problems but cant figure it out. while hes driving down the road, for no aparent reason the speedometer will start to go crazy, the transmission wont like shifting, and the engine will start to sputter. then as mysterously as it appears it disapears...

its like the truck thinks its turned off for a few seconds. the doors unlock like you turn the truck off, and when it goes back to normal the doors will lock back like you just started it. it seems like i remember something about a bad speedometer cable being able to do all of those symptoms on new trucks but im not sure. any ideas?

 

Most likely the iginition switch is bad. I think there is a bulletin on it.

 

the truck wont actually shut down. it seems like it goes into neutral for a while, then the speedometer starts shooting back and forth from 70 to 100 to 35 to 85 to etcetcetcetc. then it will shift really hard in and out of gear and the motor sputters a little bit if you stay on the gas. and then it will magically go back to normal.

i figure it could be the speedometer cable because its wired into the trucks computer. since its in the computer it could have alot to do with the transmission and doors locking and unlocking. maybe the sputtering and all is the computer freakin out with the speedometer shooting all over the place and it advances and retards out of whack. lol im just rambling. im guna unhook his alarm and electric start tomorrow but i serously doubt that thats whats doing it.

grounds have been checked. it has a brand new battery and cables now. im stumped.

 

Well the new truck dont have speedo cables. The speed sensor on the tranny.transfer case controls the speedo and works with the shifting. Id say try the ign switch. Crank uo the truck , pull on the tilt lever and bounce the steering wheel uop and down. This will usually jar the switch and cut it off , Sometimes.

 

ill try that. if im lucky that will fix it because my dad owns a business called turn key column repair in houston. he repairs columns on stolen cars and fixes airbags on wrecked cars. hes never heard of this problem in 20 years of doing it but its worth a shot.

 

sounds to me like it may be a faulty pcm.... but that's just a thought

 

this weekend im replacing his ignition switch, taking off the alarm and electric start, unpluging all of his sterio equipment, rechecking all of the grounds again geting him to take off his hypertech programming and let him drive it for a week or two and see if it makes a difference. if that works ill figure out whats doing it from there. thanks for all of the help and if anyone has any other ideas please share