airedale360

So a few weeks ago my car started to jerk and chug when idle, accelerating, and jerks really bad at 55 mpg. Gas tank was at 1/4 at the time. I went on this site and it suggested to clean out fuel tank and change filter. So I bought sea foam, which made a huge improvement, and change out my filter which was a b. now my filter is in and just filled used the tank and my jeep is still jerking.

Do you have any suggestions on want to do next? Maybe water is in the tank, or I need to replace something else?

My jeep:

91 lardo Cherokee
4 liter
4wd


Thank you

bloddy mud

What kind of fuel pressure do you have at the fuel rail?

airedale360

Well it's a fuel injected system the actual filter I will have to look at when it get home

bloddy mud

I'm thinking your fuel pump. that's y I ask bout pressure

Unknown XJ

On my '89 that I used to own, the plug wire got pulled out of the boot a little bit on cylinder #6 and it caused an arc over to the transmission dipstick. That thing would jerk and hop like crazy.
I was pulling my hair out trying to figure this out. One night I happened to be under my hood and noticed the tell tell arc coming outta the wire to the dipstick. Turned her off and pushed the wire in the boot and it was over. XJ's can be funny sometimes lol.
Don't give up though they are worth the time and blood you put in them.

airedale360

So I don't know what my fuel pump is. From what I can tell based on other forums. Is my fuel pump is running fine. It get a smooth injecting sound when I switch my key to the on position. Other suggestions were an O2 sensor but no check engine light has come on. My concern is if I keep driving it will will become worst again, it acts like a cAr that needs the carborator cleaned except it doesn't have a carborator!

It does run a bit better when I warm my jeep up but the idle is still rough

Anything else you can help on would be great I would prefer not to take it to my mechanic

As for the wire suggestions could you clarify that please?

Thanks

Bustedback

How old are the spark plugs, cap, rotor, and wires?

airedale360

Wires unknown. I figure about 4 years when my new engine was put in. The others I do a tune up on those once a year I do think my spark plugs need a tune up soon.

Could that be it? My spark plugs?

Unknown XJ

The spark plug wire got pulled out of the boot..... The thing that connected to the spark plug itself. The clip inside said boot was exposed about a 1/4 inch. Causing the spark to jump to the transmission dipstick instead of the spark plug.
If the plug wires were removed without pulling on the boot then its a safe bet its backed out some.
Also check your plug gap while you are at it. XJ plugs are gapped over at .035.

airedale360

So it turns out it was a bad spark plug. Plus the rubber on the wires were falling apart so I replaced those too. Idle it still dripping but at least it drives better!