Hey guys, new member sort of. I have an 05 Nissan Titan with a Stillen Supercharger. I have been having an issue with part throttle acceleration for a while now. It seems to be sputtering/stumbling between 50-80 mph at about 1/2-3/4 throttle. About 6 months ago I datalogged the truck and it showed that AFR was between 10.?-11.? under boost. However this setup uses a crappy piggy back tuning solution, so nobody really knows whether those AFRs are actual or not. Does this sound like a fuel or ignition.

Another thing about the kit/setup is that it uses 8 secondary injectors atop the 8 stock injectors. The pump supplied was only a 190 walbro. Kit was installed at 15,000 miles and now the truck has 50,000. Maybe that helps one of you guys know what kind of problem I could be having.

Thanks in advance for any ideas and suggestions.

 

If the wideband is showing between 10.x-11.x then that is actual a/fr, commanded a/f comes from the pcm or piggy back system, can you see what each computer is commanding? Your goal is to have commanded = actual.
Since you don't know yet, at least the actual is 11's, so that's good.
Install a fuel pressure gauge to determine if the fuel pressure is adequate.

Check the maf, I've seen trucks surge with dirty mafs.

Not sure on what else your truck has, but that's a start.

good luck,