Stalling and stuttering, no codes?

MBLV

MEMBER
1998 JEEP GRAND CHEROKEE
4.0L
6 CYL
4WD
AUTOMATIC
150,000 MILES

The vehicle will randomly stall when coming to a stop, in park or in drive. When driving at higher speeds it stutters. It is like the engine dies but starts back up on its own. No codes. When the fuel gauge is low, it will drop to empty when the engine stutters. It will return after restarting.
I replaced the fuel pump. Old pump would lose fuel pressure when shut off and the fuel gauge acting strange. No change, except it holds pressure now, but gauge still drops to empty after a stutter.
I checked the ignition and found a burnt-up rotor, was surprised it even ran. Changed plugs, wires, cap and rotor. That didn't fix it.
About 10,000 miles ago, I changed the CPS with a Mopar part. The TPS has been changed and throttle body cleaned.
I inspected the visible wires to the fuel pump. I didn't see anything wrong. But most wires are in the loom.

3 Replies

JACOBANDNICKOLAS

MECHANIC
109,885 POSTS

Hi,

The idea you are not getting a code leads me to think it could be related to the crankshaft position sensor. It can fail and not set a code. However, if you run out of fuel, it won't set a code either, and since the fuel gauge drops it makes me think it is a wiring issue with the fuel pump module.

Do me a favor. Take a look at this link and let me know if anything seems to mirror what you experience.:

https://www.2carpros.com/articles/symptoms-of-a-bad-crankshaft-sensor

Next, when you replaced the fuel pump, are you confident the connector was in good condition and tight? Also, does the fuel gauge ever drop when the fuel tank and more fuel in it? Also, when it's low, does it always happen? Two more questions (LOL Sorry for so many) does the engine start right back up when it stalls? Does this only happen after the engine is warm?

Let me know.

Joe

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Wednesday, March 29th, 2023 AT 7:20 PM

MBLV

MEMBER
2 POSTS

Hi, thank you for the response. I changed the cps about 10k miles ago, with a Mopar replacement, also at that time the TPS was replaced.
This feels different than when the CPS was bad. When that went bad it would just suddenly die, sometimes it restarts sometimes I had to jiggle the cps wire to get it to restart. Now, it almost always stutters before a stall, unless I'm at idle with low RPM, but then I've been able to catch it by tapping the throttle.
The fuel gauge only drops to empty when it is low, around a 1/4 tank or less, and only after a stutter.
I double checked the connections at the fuel pump and PCM, and swapped relays. All are tight. I did a visual inspection of the exposed wires. They look good, but there is only a little bit of wire by the fuel tank, under the rear seat, and by the fire wall that I can see. The rest is in the loom. The body ground the battery looks good, but I'm still going to clean it when I get a chance.

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Wednesday, March 29th, 2023 AT 7:41 PM

JACOBANDNICKOLAS

MECHANIC
109,885 POSTS

Hi,

Try starting the engine and then wiggle the wiring in the wire loom under the seat to see if something reacts.

Also, I realize you replaced the fuel pump, but you may want to consider checking the fuel pressure to make sure it isn't low.

Let me know if you have already done that.

Joe

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Thursday, March 30th, 2023 AT 6:19 PM