I hope this isn't a repeat question. I have searched the forum and couldn't find my problem. I have a 2001 4x4 with the 2.3 6cyl. It seems like I have a loose wire or intermitent ground.

The problem: Usually but not always happens when I go over a bump such as RR tracks. The engine cuts out for a split second, and the instrument cluster flashes like when you start the car and all the instuments go through an init sequence. Everything returns to normal after the init.

What I have done so far:
1)Changed the ignition switch/harness with a new one
2)Tried a spare ECM that I have
3)Checked all 3 ground wires ,that originate at the battery, for tightness
4)Pulled the engine compartment fuse box and inspected wires and plugs for tighness.
5)Visually looked at wiring harnesses in the engine compartment
6)Have wiggled all the wiring I can reach while it is running
7)Pounded on fuse boxes trying to simulate road bumps

Just wondering if anyone else has had a similar prob. Sure seems like the ignition switch changeout would have taken care of it, but the bug is still alive and kickin. Only does it once in awhile but someday I will be stranded. Guess I better keep paying my towing insurance. I just hate ignoring a known problem.

I am a retired electrician so guess I will have to obtain a schematic and try to find it. The bad thing is, that it is intermitent, and may check fine until it gets a good bump. Any ideas would be appreciated. Thanks

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I know you said that you checked all the underhood wiring, so I probably won't be of much help, but I had a similar problem with my 2000 Jimmy. Pretty much same symptoms, although even smaller bumps would cause the condition you mentioned in my truck. It turned out to be the positive battery cable had a very small tear in the insulation, and was rubbing against the car body. It hadn't happened in a long time, so I "forgot" about it, but then it finally shorted out, melting the wire through and sending the current through my brake master cylinder and ABS, frying it. That sucked.

 

Thanks for the tip, porkfriedrice, I will look at the positive cable a little more closely. Sure don't want a meltdown. What you described would certainly create the symptoms. Just like someone turned the key off for a split second.

Thanks

 

Just reporting back that I found the problem causing my cluster lights to flash momentarily. Turned out to be a ground at the starter. A wrench had fallen down and was resting against the hot starter terminal. Wasn't even my wrench so it has been there for more than 4 years. Finally jostled its way around to making contact. Really hard for me to believe, cause I have been on some pretty rough roads. Wrench is pretty chewed up with the lightning show going on down there but is still usable. A new ECM and ignition switch later, it turned out to be something really basic. I guess I started making assumptions too early. Lesson learned!!

A big thanks to porkfriedrice for steering me in the right direction.

This Forum Rocks. Praise GOD for answering my prayers.

 

I've gotten a lot of help on my short time here, so I'm glad I was able to help someone in return.