ok i took my truck off my sct tunes for like a 1-2 weeks finally reloaded my tune 87. and rode around for like 15 mins went to a friends loaded my truck with a trailer with alot of pallets for the bonfire we were about to do.. after we got the trailer loaded i put it in drive and started to drive to his house. got alittle down the road and the truck started struggling backfiring almost dieing luckly it was only 2 streets over. pull in front of his house and i put it in park it revs up to 1k-1500 rpms stays there for like 30 seconds then drops to like 200 rpms and starts dieing quiting then trying to stay running. it died. so i tryd setting my truck back to stock tune thinking it might be the tune.. every time i tryed to take it back to stock it would go through the entire process get to 100% then it says please turn key off press select i do that and it says verified failed would not let me go back to stock. so i had to take negative battery cable off then put back on and it would run right for maybe 5 mins and start all over.. tryd to go stock again still wouldnt.. got mad and reset the comp so i could drive it home. this was all yesterday.. today i went out and tryd to put it back to stock and it worked but before that i started the truck and let it sit for like 20 mins at idle got to operating temp and drove it around my house. it has not done it today but i dont want to chance it.. could this be the tps or another issue? local part store quoted me 33$ for a new tps


EDIT i emailed hemifever he stated if it was having problems going back to stock i needed to call sct. EDIT truck finally went back to stock just had to wait a day dont know why it would go back that night but when i got up in the morning it worked.

 

TPS is a pretty good bet. You can test it with a meter.... should be a smooth sweep from less than one volt at closed throttle, to greater than 3.5 volts at WOT. If it jumps around at all, replace it. (also, if it is out of spec at either end, replace it.)

 

Not the tps. Got a new one and its still doing it.. could it be the idler control valve or mass air?

 

If you haven't cleaned the throttle body yet, try that first. You can verify that the IAC is working afterwards by lookin' down the "hole" where you can see the pintle, when someone else turns the key to On, (not start) the pintle should go all the way in, then back off a bit. If it doesn't do that, it's bad.

Also..... if it runs good cold, and starts doing 'bad' stuff after a couple minutes, that's a sign of a failing O2 sensor.

 

Tb has been cleaned took iac out cleaned that. Still doing it.. also it usually only does it when warmed up.. and weirdest thing happens when it starts doing it.. my check engine light is always on but it goes off light its resetting itself so there are no codes.

 

how old is your O2 sensor?

 

Im not sure. I know i dont have a pre cat o2 been like that for years just have the post cat.. trucks been fine till now

 

Edit.. replaced the iac did not fix it.. soon as it got to operating temp problem still there

 

You really need that pre-cat O2 sensor... I am real surprised the truck doesn't whine about that.... If it is using the post cat, and thinking it is the pre-cat.... that would indeed cause some truly odd performance problems. Especially after it warmed up.

You could also be experiencing the beginning signs of a failing crank, or cam sensor.....

 

is there any way to test.. also when it starts to act funny.. my check engine will be on but soon as it starts to die the computer like resets itself or something.. the engine light goes off and if i try and start it back up she will fire up but will die.. and the engine light will be off. opened up my tb and looked down at the pleneum looks reall good and clean. alittle black on one side prob from where i cleaned my tb awhile back cause it was dirty.. but everything in there is bare metal looks new.. since ive had the truck i havent changed it 140,00 miles when i got her. now im at 214,000