Multiple misfire codes !
 

96 850 glt {non turbo}. I just returned from a 2400 MI. trip from Mi. to Fl. and back. CEL came on after 1400 MI. P0172. This has happened before and I changed out any bad vac. conn. and lines I could find and all problems fixed.So I checked conn. and all looked good so I waited until I got home for further inspection. I did find a bad connector and replaced it. When I went to clear the code I had codes P0300,301,304, and 305 all misfires. Could the travel of 1200 Mi. with code P0172 running rich have caused the further problems? Looking to clear up these codes anyone have any idea's? As always thanks for the help.

Man you're going to have to find the problem. I doubt that the P0172 is causing misfires. Maybe you have a fuel pressure problem or something. Did it ever run funny?

When was the last time you tuned it up? How old are the wires (they have a date on them)?

Running rich over an extended period could well have fouled the spark plugs. You might want to pull a couple and see if they look blackened with soot.

RSPI I did a complete tune up a few years ago. Everything checked out fine before I left for this trip no codes. I normally drive back and forth to work good for about 1500 mi. per yr. The car runs smooth as always.

K4F I'll check the plugs. On the way home from MI. between the snow storms and all the rain in FL. it was almost bumper to bumper all the way. I'm wondering if I should just due a complete tune up.

I would recommend pulling the plugs and inspecting, same with the rotor and cap. Replace if you're in doubt about their condition.

To test the ignition wires, remove the cover and get an empty spray bottle and put some plain water in it. With the engine running and either in a garage or outside in the evening when it's a bit darker out, mist the wires with the squirt bottle. If the insulation is breaking down you will hear and usually see the spark jump to ground where there is a weakness in the insulation. Do not touch the wires as you'll get a good shock if they are weak.

+1! That's the way I test old plug wires too!! :D

LOL, Are you guys serious?

Rspi, about using the spray bottle with water ?? Yes we are. If you think about it one of the main symptoms for bad wires is hard to start when it's wet outside. Rain water or morning dew on the wires will give them an easier path to ground than running all the way to the plug and jumping the gap.

On really bad wires you can get quite a light show from the arching beside hearing the snap when they use the water to jump.