bigraydogg

I use arco gas but 91

bigraydogg

what about the spark plug, why is it black? Does that mean it is burning oil? It was not wet just black.

PureDrifter

iTrader: (10)

second for dead spark plug wires, check with an ohmmeter to confirm.

bigraydogg

K I'll change the wires and see what happens. Thanks

RA40

iTrader: (6)

That was the old wire? That does explain a lot. Black plug is fouled because fuel isn't being burned off. That will be a pretty dirty cylinder but will clean up with proper ignition.

I read and article about BP/Arco gas and a lawsuit filed by CA EPA for their dirty fuel a few years back. I would suggest a better gas and see what it does to your MPG.

bigraydogg

that was a new wire i just put in about two mo ago. It was misfiring with some double platinum autolite plugs from autozone. I swapped those out for some NGK DP with no luck still misfired. But when I swapped the plug the boot was still good. Still misfire so I figure it might be cap/rotor. I changed the C/R about a month later because finances were low. But when I changed the cap and rotor it still mifired; actually sounded and felt worse. Thats when I pulled the plug and saw the fouled plug and burnt boot.

Luxurexus

Do you have coil packs? I had a misfire on my '91. Replaced plugs and wires but it still continued until I changed my cp's and it went away. Good luck

bigraydogg

coil packs? well its 5&7 does anyone know if they run off same coil pack

PureDrifter

iTrader: (10)

yes, you do.

all LS' til '98 had 2 coil packs, one per bank. 5&7 are on the same bank (driver's side, bank 1 iirc).

dpickett63

How do you check if the coils are bad?