Yuik87

Heres the deal about a month ago i got a tune and a week after the tune i

got an occasional slight miss from cylinder 1 thought nothing of it really. But

then about a week ago that miss turned into a big deal giving me a flashing

ses light on the way home. so i turned it off and checked the code it didnt

tell me anything out of the ordinary besides fuel level sensor circuit. so i am

gonna hafta assume that they turned of the cylinder misfire codes. After i

checked and saw nothing that could help figure out the problem i started it

up and it was fine like there never was a problem. that continued for about a

week The problem being that at idle or part throttle it would miss in cylinder 1

but not at full throttle and only after running for a minute or so and if i turn

it off and then on again fine for a minute until something happens that

causes the miss. i checked the plug and wires there appeared to be arching

cause the plug had burn marks on it as did the wire so i replaced them and

later on the coil just trying to fix the problem. so i dont think its a spark issue

maybe leaking injector but i have no clue why it would only do it after

running for a bit. It doesnt do it every day either just when it feels like it i

drove 156 miles and no problem but then on my way to and from work it

crapped out so i dont think theres any reason for when it does it. If there is

anyone that can help i would appreciate it immensely. and sorry for the long

post

jimmyblue

iTrader: (11)

End-of-rail injectors are the first to silt up in dead-end
rail setups (i.e. most). If the tune pushed fueling leaner,
that was based on an average AFR result and if there
is injector delivery imbalance, may "expose" the weak
ones (leaner than average, -> misfire @ load).

Swap #1 for #3 and see if it moves. Though I gather
sometimes the misfiring cylinder index can be off by
one; maybe pull the plug wire first and verify that
#1 is #1 on the scans (should be humongo misfires
from that).