The strangest thing happened yesterday...

Fist I will say in the past month or so on a few half hour to forty five minute drives I have had a strange miss, for like a second or a millisecond the Jeep has cut out, almost felt like a quick hit cut out or miss then drove fine. Then yesterday while driving, about a half hour in it just died, completely shut off on the highway. Pulled over and started right back up. Drove another hour or so the rest of the day and not an issue?

All gauges are fine, I have a mechanical fuel pressure gauge, haven't been able to check that yet.

Wondering where I should start with this?

99 xj with 96 rebuilt block, around 10,000 miles in so all sensors and anything connected to the engine are 99.

 

Definitely confirm your fuel pressure. 49 PSI @ idle with plus or minus 5 PSI tolerance.

Also, another major contributor of this problem is bad connections. Both positive and ground points. Most notably, the battery terminals/posts. Have your battery tested as well. Clean battery posts and terminals with a wire brush until clean. Apply a thin coat of dielectric grease on terminals and posts. Probably a good time to go through the vehicle and clean up your ground connections.

 

Cam or crank sensor, maybe. Or even the ASD relay. Have you checked and cleaned the grounds lately? Any codes?

 

No codes.

I will start with all of my grounds and electrical connections.

Will double check fuel pressure as well.

Thanks, will let you know how it goes.

 

This is very similar to what happened when my CPS went bad. Were you on the throttle to pass a car or get on the hwy when it happened?

 

yea I would say if OP doesn't have any luck with our first suggestions, it definitely sounds like a CPS issue.

 

When it shut down I was speeding up from a stop but the other times I was cruising around 70 on the highway every time.

 

This sounds like CPS to me. I would have cruise set on 75 and when it would go to speed back up like on a hill it would die.

 

I agree it sounds like CPS, but...


I had a very similar problem that turned out to be my O2 sensor.

Still, I'd look at the CPS first, and keep the O2 in the back of my mind.

 

good call

 

Thank you guys, going to get a look at it this weekend.

 

Just a follow up to this so hopefully it can help someone else out.

Started off with all connections, thinking maybe we slopped one when we swapped the engine. All were good and batter connection is in good shape.

I ended up pulling the distributor cap and notice what you see in the pics. Rotor and cap looked very rough. I had a set laying around so I went ahead and installed them. While I was at it I replaced the cam position sensor. I thought I had the issue taken care of but the same problem came back, intermittent stalling and a hard/light miss while driving.

I broke down last weekend and paid the $135 for crank position sensor and it solved the issue.

Was maybe an hour start to finish. I dropped the cross member on a jack for better access and use duct tape inside of the socket with the sticky side towards the socket to hold on to the bolts when putting them back in (See pic).

Wasn't a big deal just took my time.

Thanks for the suggestions everyone!

 

Thanks for the follow up!