3100 sfi cuts out at WOT?

[SwiftDrift]

i had a 90s grand am with the 3100 sfi, but it did not have the lines on the plenum, indicating that it was a later intake. (not sure if that has much to do with it?) and it also had a hollowed cat. but anyway when the pedal hit the floor it would seem like it was about to stall, then it would pull. it only cut out for like a second. im not really looking for a fix as i no longer have this car, but i would like to know exactly why it did this.

ps: i wasnt sure where to put this post so i put it here :P

[robertisaar]

TPS would have been my first guess. or at least, some other cause of not enough extra fuel not being injected due to quick throttle transitions.

[SwiftDrift]

it doesnt do it on the grand prix.. so i take it this isnt a common issue?

[robertisaar]

if either the TPS is slow/faulty or the transient fuel calibration is no longer correct, either could cause it. combined, lots of trouble.

the large port intakes act differently enough from the small ports that a proper calibration can make a world of difference.

[SwiftDrift]

Maybe the previous owner swapped the intake and called it good.

[3400-95-Modified]

94-98 had the L82 3100 engine which is the small port 3100... The 99-05 came with the LA1 3400, so if you have a 3100 plenum without the lines and the UIM is bolted to the lower with only 6 bolts then someone did a large port upper intake or full engine swap and probably didn't have it tuned. The Large Port 3100 engine was never an option for the GA's.

[SwiftDrift]

yeah i thought it could be from the plenum swap.. all i know is right after the "lag" it kinda put u in the seat must have been a motor swap using the chip that was already in it?

[3400-95-Modified]

What year GA is it? It may not even have a removable chip... I'm not sure what they did in 94-98 vs what Beretta's had but I know 94-95 Beretta's were not tunable until recently, they were flash style OBDI systems, no chip to remove.

[robertisaar]

the only 3100s to use a MEMCAL were the 94-95 A-bodies.

[SwiftDrift]

pretty sure it was a 95.