99 Miata engine cuts hard cornering or sharp bumps

Having a intermittent problem with a 99 Miata.

When I hit sharp bumps or corner hard, right or left. The engine cuts out only for a split second.

I have checked the battery connection, the fuel pump and strainer are new, plugs and wires are new, although the problem predates the plugs wires and fuel pump.

I checked the seat for the relays and tried jiggling the wiring harness wherever it was easily accessible, but can't duplicate the problem.

Anyone have any ideas about where I should start?

Edit Forgot to add that everything else electrical stays on, radio fan headlights.

How are your motor mounts?

Check the ground wire from the block to the chassis?

In reply to RossD:

Motor mounts are in great shape car despite it's age is low mileage.

In reply to EastCoastMojo: Will give that a check. See if it needs cleaning.

Check any plugs/connectors that involve the engine harness.

Any chance the knock sensor is acting up with age?

With it idling, go around and wiggle every wire and connector you can access, and the problem isn't necessarily confined to the engine compartment.

Thanks for the suggestions. This backs up my hunch that it is electrical in nature.

I thought I had it solved; I saw a post about the battery possibly grounding out against the chassis. I looked at my battery and noticed the positive terminal insulation was wedged against the body. I repositioned the battery but no dice.

Check the ground point on the front of the intake manifold near the throttle body. That's where all of the electronics ground through, if the bolt is loose then the engine will cut out under vibrations.

Had this happen on a chumpcar. It was battery making connection with the trunklid or top of the trunk due to a larger than stock battery.

Checked the ground and the battery. Battery was fine -not grounding-. The ground contacts were a little corroded so I cleaned them, but the problem was still there. I added a second ground, but it didn't make a difference.

Edit*** I just got to work car sat overnight and it was cool out. The problem didn't seem to occur may be the temperature makes a difference. Or it may be that I drive it a little nicer until it is warmed up.

Crank angle sensor loose or oil/grime soaked?

I've had a similar issue on an NA Miata. Turned out the one of the wires in the harness running behind the distributor had broken inside the insulation. As previously mentioned I reproduced the problem by wiggling every wire I could find. Ended up replacing the connector and length of harness, then adding a bit of heat barrier. I suspect the worn engine mounts may have been caused the wires to flex more than designed.

PMRacing wrote: Crank angle sensor loose or oil/grime soaked?

Ding! Ding! Ding! Ding!

That is exactly the cause. I took off the under tray which took longer than the fix. Cleaned the crank sensor, checked the gap and checked for looseness and checked the 4 teeth on the crank pulley were still there and not damaged.

For the record, it was filthy. I cleaned it, then took some degreaser to the area surrounding it. Took it for a drive, problem solved. Thanks to all for your suggestions. In particular PMRacing!