Engine Turns Off While Driving Is300

[hatc9550]

I am stationed down in Corpus Christi Tx and there are no lexus mechanics or dealerships here. My lexus has thrown no codes

on the diagnostic. Sometimes as the car hits bumps it sputters like it has bad gas in it or there is a grounding problem. I have a grounding electrical kit on the car. I've also replaced the air flow meter and that seemed to clear the problem up for a while then it got worse again. The car does not seem to act up when it goes into the toyota dealership only when I'm driving it. Has anybody had this problem? When the car begins to sputter I can accelerate through the sputter but when I am sometimes at low speeds low engine RPM's like exiting the freeway it just dies but the battery is still on and I restart in neutral. Could it be a fuel filter? Gas cap??? How often should a fuel filter be replaced????????????????????? Does anyone have an idea? Thanks

[smooth1]

You say when you put an air flow meter on it fixed the problem for awhile? And it does it when you hit bumps?

What grounding kit do you have on the car? Have you checked all the connections? The grounding kit would be my first guess. Bumps may be jarring a bad connection. I would especially check the wiring to the MAF sensor. Maybe even clean the MAF and see if that helps also.