KnoxJeep

Rolling down the hwy, felt a couple of momentary losses of power ( like a real hard miss in the motor) then she just shut off.

Got it going with a jump and thought alternator for sure but it tested great under load. Battery is fine. It's started up just fine a few times after that but every once in a while it'll do that "hiccup" where it feels like it's gonna cut off again.

Thoughts? Crankshaft position sensor ? Anyone have a good test for cps?

Thanks fellas

KnoxJeep

Forgot to add: 99 w the 4.0

KnoxJeep

Also - no check engine code present

JD Cravin

Those were very similar to my symptoms when my cps was going out. Replaced it and all cured...not saying this is exactly what you have but they sure sound similar.

Turbo X_J

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KnoxJeep

What year is yours and how hard was it to get to?

JD Cravin

98 and I used the write up that's posted on here in the write up section...difficult and awkward to get to but doable.

Bustedback

My ZJ did the same thing every time I hit an expansion joint or pothole on the freeway, replaced the CKP sensor and the problem was solved. Look at the tach when the engine starts acting up. If it drops to nothing fast I would suspect the CKP sensor.

jomps

loose connectors at ecu?

KnoxJeep

Connectors are good. I'll be replacing cps tomorrow after work. Think I found a spot underneath where I can get to it. Thanks for the advice, I'll update when it's done

DFlintstone

I have this for older Jeeps. Yours is pretty similar I think ;

To change your CPS I found if you BACK the fronts onto ramps, you won't have them in the way, where you need to lay. A stand under the left front frame would be in your way.

11mm socket > 3 inch extension > universal > long (18-24 inches of extension). Your feet are sticking out under the passenger side, you can reach up past the front drive-line with your left hand to hold the CPS from the front. Your right hand is on the ratchet way back by the tranny cross member. If you tie a long string on the old plug, you can use it to haul up the new. Toss that piece of plastic if it's still there, and do not drop the bolts in there!

If your left forearm is bigger than a quart Mason jar, you might consider removing the front drive-line. Also You might cut your old CPS wires if they go through a deal on a bell housing bolt, then be sure your new are held somewhere safe.

The second one is REALLY easy!

KnoxJeep

So.... Replaced the cps tonight after work. That was tough to get to but did it in about an hour, here's how: if you lay perpendicular to the front driveshaft with your head near the front left wheel you can see the cps by looking over the front driveshaft - having the hood open allows enough sunlight in to see the 2 bolts. 2 extensions, a universal joint, plenty of pb blaster and a flex head rachet got both bolts loose. Tie some string from the old one to the connector on the new one and pull it up. Couple of swollen forearms but its DONE!!

Now to drive it tomorrow to work and see if it works. Drove a few miles after fixing tonight and ran well

Thanks for all the advice