Running fine during day but at nite ???
 

I got an '88 Iroc with a 383 stroker in it with stock ecm and prom with a 5 speed. For some odd reason during the day it'll run fine and I can have it wide open throttle and hit high speed with high rpm's. However during the nite when i try to reach high rpm's and high speed's, the car will spitter and sputter and i can go full throttle. I completely ran out of ideas, i changed spark plugs, opened up the gap on them, the icm is new and good working, wires are getting at spark. i jus dont know wat it is. please help me, i trying racing some mustangs and this happens. Thank you for any help :thanks:

Re: Running fine during day but at nite ???
 

do u have a mass air sensor, if so u can clean them. i have to clean mine monthly or it gets a stutter especialy at night

Re: Running fine during day but at nite ???
 

how do i clean it because i descreened mine

Re: Running fine during day but at nite ???
 

probably has to do with the lower outside temps at night. get it tuned to run properly at all temps, get some datalogs and post it up in the diy prom board.

Re: Running fine during day but at nite ???
 

ok, im gonna have my buddy do that when he attepmts to tune it this weekend. hes got the labtop, the chip burner, everything that I need to burn my own chip. its come pretty neat stuff of wat he can do on this lil labtop

Re: Running fine during day but at nite ???
 

Maybe low voltage on the ignition when the lights are on?

Re: Running fine during day but at nite ???
 

Nah belt it tightened to the max and the alternator charges jus fine