five0killr

iTrader: (2)

just put longtubes on my friends vette and we checked out the ignition real good and it seems to be ok. under a load at a low rpm it pops and misses pretty good..not quite so bad at a high rpm anyone have an idea?

Mike K.

hmm I was gonna say ignition but you said you already checked that? Maybe swap the spark plugs just to be sure you got the gapping correct. If you have another friend with an fbod or vette maybe they would be willing to swap spark plug wires and coil packs as well to be sure. Only other thing that might make sense is an exhaust leak but Im not sure if that would just sound like crap or give you the results you experienced with the missing and popping.

five0killr

iTrader: (2)

as far as ignition goes...we took all the plugs out..and checked gapping, and it was good..and i made sure i could see spark coming off of every coil pacl by macking it shoot out off the coil pack to my screwdriver....so i dont think its an ignition issue..its definately got my boggled......could it be somehting with 02 sensors?

WS6FirebirdTA00

iTrader: (33)

possibly could be the o2s. try swaping the rears to the front and see if the problems goes away. did u check all the spark plugs to see if the spark? if they were on when u did header install u might hvae damaged one, maybe. let me ponder on this for a little more...

WS6FirebirdTA00

iTrader: (33)

how did u do the header install, what was taken off and did u do it from the top or under the car?

five0killr

iTrader: (2)

all the coil packs were removed so that they would fit...and we checked em all for spark...the plugs looked good..nothing noticable..and the gaps were all ok when we re-installed them..i just cant seem to figure this one out..thanks for the help guys

WS6FirebirdTA00

iTrader: (33)

ok they all spark, but do they all spark consistently and at the same pattern? dont know if its possible to have a spark interval being off wihtout the whole coil being dead. only other thing i can think of is the o2s man i would give it a shot and throw the rears in. the rears dont affect the way the motor will run so u can leave those jokers out. it will throw a code but dont worry. only other thing is if they dont fix it u might need some tuning pretty bad....dont know what else

blk~2000~Z28

I HAD the same problem but just not as harsh as you are describing. Is it throwing a code? If it is throwing a code check that code, I was able to determine what cylinder was missfiring and I found a faulty wire after narrowing down the problem checklist.

WS6FirebirdTA00

iTrader: (33)

yeah if u have a plug wire that was laying on the header and melted it could be grounding out on the header. did u check for that? just another thought for you

distortion_69

iTrader: (20)

I have fireworks like popping on decel, and a slight
noise if I keep the rpm steady at any given rpm range
cruising. It doesn't have the "feel" of a miss, but it does
have like a "phlut... phlut" almost airy like sound when I
hold it at say 2k.. Do you think this might be the same
thing you are describing but not as noticable?

blk~2000~Z28

Are you receiving any codes for this problem? It really helps to clarify or narrow down rather what the problem is or is not.

WS6FirebirdTA00

iTrader: (33)

what year is the car we are having the problem in my friends t/a. idles ok but rough and it revs fine but under load it sucks. we have done everything besides fuel pump were gonna do tomororw night and if that doesnt fix it we are gonna get injectors