ToxicWS6

so long story short ive been pulling my hair out tryin to figure out why i stumble choke bad under slight throttle at first when first hitting the gas, my A/F meter goes dead lean and then picks back up like it should after 1-5 secs of stumbling, depends on speed rpm and how hard i hit the gas, car drives and pulls great everywhere else

well today while doing a coolant flush i was playin with the throttle by hand and if i hit quick or held for a min it just stumble/miss bad like it was about to die and then rev up or if i let off back fire into the intake

ive been trying to think what it could possibly be, thinking it was something to do with the tune when i switched to 60# injectors, (thats not 100% ruled out but ive changed everything u could in the injector settings and things changed but still had same lean spike issue) and it dawned on me that it could of started right when i took my TR6s and went from a .44 gap (i was blowing spark out under 12psi of boost) and just took to .22 gap

should of i stuck it with .28? and would this be my issue?

jaxcam02

iTrader: (1)

I can't help with that but maybe you would get more views on the "General Maintenence and Repairs" category.

LilJayV10

iTrader: (39)

If it's going lean when first hitting the throttle it could be a lazy TPS or the PE table needs to be adjusted.

SSellers

Rich misfire can read lean on the gauge. Had a problem with my archaic system doing that. Started out with not knowing that vac advance wasn't pulling in at light throttle and had tuned everything for what it was doing. Once finding that and fixing, my accel enrichment at low throttle angles was way too rich (rich mix needs less timing, lean mix needs more timing) so had to trim those down. Problem fixed. Might be a combo of the gap and a little too much fuel dousing the spark.

1 FMF

iTrader: (1)

well some small 4-stroke single cylinder engines run spark plug gaps down around 0.020-0.025" and they had no problem with combustion and that's with a much weaker ignition system. unless you have a different ignition setup than oem, you have a coil for each cylinder and plenty of spark energy. in my opinion going to 0.022" of a spark plug gap is overkill, i don't think you should need to go less than ~ 0.035". if you need to do that to "prevent blowing spark out" then the problem is not with your spark plugs and spark energy from the coil.
what spark plug gap do some oem engines that are forced induction use?
if they are running typical gaps of 0.040-0.050 then spark plug gap isn't your problem.
from what i've read and seen over the years, i'm surprised how you can think it's not the tune. it's always "the tune" that's the problem or at least a biggest part of it.

1 FMF

iTrader: (1)

and you said car pulls great everywhere else- i assume that means at full throttle at 3000+ rpm there is no problem. if that's the case you don't have spark blowout- you're not blowing out the spark but rather cylinder pressure is so high that there's not enough spark voltage and energy to jump the current gap at the spark plug; so you either reduce the spark plug gap or increase ignition coil output.

when you snap the throttle during a low load state, you have high intake vacuum. there is no pressure built up in the intake under this condition, although you didn't mention what your setup is all i know out of context is you mentioned 12 psi of boost. so under this case it has everything to do with "the tune".

ToxicWS6

i was having spark blow out at .44 gap so i had to gap them down i kept hearing from .22-.28 gap so since i was running high boost lvls or plan to i choose .22 thinkin there wasnt going to be an issue

i was blaming nothing but the tune but it happened close to the same time i regapped so i was just double checking it wasnt

i do need to touch up my tune after some more logs i noticed things, and it goes off charts "lean the. rich then 15s, im thinking its soakig causeing missfire and a lean reading imo, it stumbles when it dosnt also