99 xj 4.0 running like a turd

[crossoffroad]

So i have a 99 4.0 4x4 xj with around 220k miles on it. I come from a motorcycle building background and im not sure how some of sensors and ect cause what symptoms in an EFI engine, so here is the deal.
My oil pressure alternates between 18-45, it it idles really noisy at hot and cold, sometimes it stutters when i start it. It throws a code for cyl1 misfire but if i unhook the injector plug or spark plug there is a change in the idle and then sometimes it runs perfect smooth and quite usually after long drives. Im getting a compression tester tonight anyone have any ideas for me?

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[denverd1]

no other codes?
idles noisy? like a tick or what?

[abebehrmann]

So i have a 99 4.0 4x4 xj with around 220k miles on it. I come from a motorcycle building background and im not sure how some of sensors and ect cause what symptoms in an EFI engine, so here is the deal.
My oil pressure alternates between 18-45, it it idles really noisy at hot and cold, sometimes it stutters when i start it. It throws a code for cyl1 misfire but if i unhook the injector plug or spark plug there is a change in the idle and then sometimes it runs perfect smooth and quite usually after long drives. Im getting a compression tester tonight anyone have any ideas for me?

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What does the spark plug in cylinder 1 look like?

I'm thinking either that or a plugged up injector.

[crossoffroad]

It looks good i swapped it with c2 and it was fine.

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[crossoffroad]

No other codes. A deep sounding knock and a bit of a mid tick

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[crossoffroad]

Not really loud though very light but you can feel the engine vibrate thru the jeep when it's doing it and my RPMs will bounce up and down.

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[Pookapotamus]

Test the compression and get back to us, is it coil on plug or single coil?

Does the oil pressure change at idle? Or when you rev it up?

When it stutters on start up is it hot or cold or both???




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[Pookapotamus]

The deep sounding knock? When do you hear it? As you start to rev??


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[4.3LXJ]

When was the last time the plugs and O2 sensor were changed?

[crossoffroad]

I dunno about the O2 sensors plugs are probably due. They all looked pretty good though. Knocks on and off randomly.

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[4.3LXJ]

If you are getting a knock, as in preignition type knock, I would suggest using some seafoam in a 1/4 tank of gas and take it for a nice drive, change the plugs and O2 sensor then we will have a clean slate to work with

[crossoffroad]

I already seafoamed it blah. Ive decided, its time for an engine swap.

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[denverd1]

220k isn't much. You could take the pan off and check things over. Any blow by?

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[crossoffroad]

No it honestly runs pretty good, im just paranoid i think. Its probably a sticky lifter of valve.

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[Pookapotamus]

What were the compression numbers??


Having 4WD means getting stuck in more inaccessible places!