2000 Jeep Grand Misfire problem not coil Pack

[Chrisfromalbany]

2000 Grand Cher V8 4.6 Liter
have check engine light (missfire cylinder 8)
P0308 (Cylinder 8 Misfire Detected)

I replaced the coil pack for this cylinder (tonight) which I believe this one to be the farthest cylinder on the passager side of the engine. A real [censored] to get to and replace.

But still when driving up a long and tall hill Jeep will buck to some degree and seem to lose power. I thought this was coil pack failing to give good charge under heavier loads but that doesn't seem be case. Under most driving conditions the engine seems fine. Also when starting up the hill for quite a distance the engine runs strong and hard just midway through engine starts to buck and lose of power.

Think I fine strange is Jeep seem fine that shows the problem, then seems engine wants to buck more after showing the problem. Going to work to mostly downhill and going 75+ isn't an issue with it bucking.

Any ideas?

Thanks,

Chris

 

[crazyoildude]

Fuel filter/ pump?

 

[Chrisfromalbany]

if that was case wouldn't I see the misfire on numerous cylinder not just 8? that does seem to make it way sense... Because doesn't seem do it all the time just under heavier load.

 

[Zaedock]

Check for a clogged injector.

 

[spasm3]

Perhaps an injector problem causing lean misfire?

 

[berniedd]

It could be a bad plug. Exchange that cyl's spark plug with another and see if that migrates the problem to the other cylinder.

 

[Scott_Tucker]

Did you replace the boot that runs from the coil to the spark plug? This is a common failure item. It's analogous to an open spark plug wire.wire.

 

[Chrisfromalbany]

Originally Posted By: spasm3
Perhaps an injector problem causing lean misfire?


ok so seems like could be spark plug or injector for #8.

 

[VNTS]

what plugs, how many miles on them, how many miles on the Jeep.

 

[Rob_Roy]

It is not uncommon for a failed coil to also result in a fouled spark plug. Replace the plug, and the other 7 if they are due. Any vacuum lines attached to the intake near that cylinder? A vacuum leak in that area can cause a lean condition.

 

[jeepman3071]

Pop the valve cover and check the rocker arms. The early 4.7 V8s were known to have loose rocker arm problems which could even result in misfires.

 

[Chrisfromalbany]

179K miles on Jeep.. Sorry should have listed that before.. don't know how many miles on plugs recently got the Jeep as trade for a bike.

 

[Chrisfromalbany]

now I have been driving the truck and the check engine light gone off.. is it possible that I can get truck inspected if the light gone off w/o clearing the codes or pulling the battery lead.