changed plugs-now missing

[lawdog49]

changed plugs in my 91 350, now i have a really bad miss.  so, i changed the wires too, but that didn't help.  i changed all the ones on the drivers side first, cranked it and it ran fine.  after doing the other side i have the miss.  i checked to make sure i didn't pull a vacuum line off or something- any other ideas?

[ccz145a]

bad plug - crossed wire, it's something that just happened. retrace your proceedure

[VileZambonie]

You probably crossed a wire or crushed the gap on one of the plugs.

[Lt.Del]

make sure your firing order is correct.  Look at the distributor, the wires go clockwise

18436572

right side (drivers side) is odd, from radiator 1357
left side (pass. side) is even, from radiator 2468

follow each wire ensure it is going to correct plug.

[lawdog49]

only took one wire off at a time, changed plug, and put wire back.  changed plug wires yesterday one at a time.  also took every plug out of the passenger side, one at a time, and looked at them- a little wet with oil but gap was fine.  i don't know how to read plugs- should they have oil on them??  i'll double check wires and firing order, but only doing one at a time i don't see any way i could've crossed them.

thanks for the responses guys, this is a great forum.

[dumbucket1]

just a thought but I have had cheap bosch plug wires be bad brand new from autozone, also did you put ac delco plugs back in? I dont have any luck with my motors running well with anything but ac delco

[TexasRed]

that may not be oil, that may be gas and carbon. I've good luck with autolite plugs. Might replace that there plug and see if it starts hitting on that cylinder.

[lawdog49]

delco 43ts plugs and napa's best wires- but the wires didn't change anything.  think i'm gonna go ask for some replacement plugs and try them one at a time.

[Lt.Del]

but only doing one at a time i don't see any way i could've crossed them. 

happens all the time though.   I simply take all wires off the cap and start from scratch each time.  I go by the firing order and place the wires on accordingly.

did you change the cap and rotor?  If by pressing the plug wires on the cap, you may have pressed hard enough to crack the cap?? just throwin that out there.   I'd replace the cap/rotor as well. 

Did you place the coil wire in correctly?

Sometimes when certain plug wires touch each other, they will cause a misfire.  I ensure all my wires don't touch any other as much as possible.  Ensure your wires are not hitting the metal frame or other ground.   did you hear the click when the wire attached to each plug/cap point?

You could run the engine in the dark and see if any blue sparks jump from any wire.

if all else checks out, take a long older plug wire you removed and one at a time, replace one of the newer wires --going to all plugs eventually and rule out a bad new wire.

[Captkaos]

I would retrace them on the side that started missing.  I would also verify connection at the plugs and at the cap.

[lawdog49]

OK Andy- I owe ya a beer if your ever in Bama!  I would've sworn that I took a wire off, changed plug, put wire back on- but somehow I apparently got #2 & 4 switched, that's why those plugs were so wet and I had the miss!!  Chris, I just read your post and your on the money too!

Thanks guys!

Now, if I can just decide what engine I want to build/buy for the beast-the 383 TBI build sounds soooo tempting, think I'll see if I can scrounge a good block to start with and have my mechanic buddy start helping me work on a parts list.