Bumpy road, engine cuts out, runs rough

This past weekend, jumped in the AV to run errands and while going down my gravel road, hit a washboard area and the engine started running rough and then cut out. She would crank, but wouldn't restart. Got out, gave it a quick look, and got back in to try and she fired right up.

Decided to keep going and hit another rough area, once again started stumbling, this time throwing a flashing CEL. Pulled over to pull the code and nothing except for the generic 300, Random Misfire. Cleared the code, now on pavement. Seemed to run fine until I hit anywhere that had bumps.

Replaced the fuel pump last year with a mid grade brand. Other than that, no major work on the engine in years.

Wondering if the pump may be going bad (if so, glad I cut the access hatch). Or could I have a bad ground or loose connection?

Any other suggestions on things to look for or check?

Check for loose or corroded power cables... And ground locations.

Rodney

redheadedrod said:

Check for loose or corroded power cables... And ground locations.

Rodney

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agree.... check for any loose connector on engine like injector or sensor wire.

This is gonna suck big time. Since the issue only arises when hitting bumps it will be hard to know if I find the culprit until I test drive, and then if does re-appear I may end up stranded from the house.

Guess I'll dig through Sperry's stuff and find out where all the grounds are and hit each one. Remove, clean, install. Then pull and reconnect each connector.

In the old days the first thing I would have checked would have been spark plug wires. 

Checking all the grounds is probably a good thing as well as checking battery and alternator connections.

Try moving different sets of wires/connectors around while idling in your driveway. If it starts to run rough you found it.

I am having the same problem. Did you ever find the problem?

I've had pretty much this problem recently, with a misfire starting after hitting a pothole or two, with a number of seemingly random codes being generated. Given it's age, I have decided that the first task (apart from the obvious) is to check out the ground points. Battery cables, at the battery are good - all tidied up when I put on a new battery a few months ago.

Today, I did the two underneath the drivers door - they were quite a mess, but cleaned up nicely. One of the bolts was rusty enough that getting it tight was a bit of a problem, so its on the list for replacing.

Took it out for a test drive and, at the first bump, the engine misfired, and the Check Wallet Light came on, but briefly and went out - the misfire stopped as well. Stayed out another 10 minutes, looking for potholes and, while I found a few, there were no further effects from the bumps.

Now to gradually clean down as many ground points as I can get at without stripping parts down too far.

GG

GreyGhost said:

The Check Wallet Light came on, but briefly and went out.

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I typically ignore that light since I know the wallet is usually empty!