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97 Mazda B2300 pickup - vehicle arbitrarily loses power while driving and while stopped

Okay, my previous post disappeared so if this shows up twice, I apologize in advance. Anyway, traveling approximately 40-45 MPH and my engine just quits. I was able to turn(very hard without power) to get off the road. I tried to restart the vehicle and it wouldn’t crank over. After calling roarside assistance and the PD, I tried again and it stated. On the same day, I was driving home from appointment and it happened again, this time while accelerating from a stop and making a left turn. Same scenario, only this time the truck turned over a lot quicker than the first time. A couple days later, it happens again while accellerating after a stop and making a left hand turn. Now I call the mechanics and ask if this could have something to do with the module they replaced for my AC. They check out the truck and get a new module to install, which they did under warranty. We also left the truck with them to drive to see if it did it to them, it didn’t. So DH takes truck and he drives it and it does it to him. Now though, with me and with him, the truck seems to start back up quicker then the first and subsequent times. We are going away for a bit and plan to leave the truck with the mechanics to drive to see if it does it to them since they still haven’t had it happen while they’ve had it. I’m stumped. They were able to fix the ac very reasonably and a few other things have popped up, but this truck has been really good to me and I’m trying to drive it into the ground, so to speak, as it still has very low mileage for its age. Of course, the thought of it just conking out while driving is very disconcerting. I wait until the roads are completely clear to do u-turns and such, but in the back of my mind, I know it can shut off anytime.

One other thing, each time it shuts off, the ac and electrical is still working; it just doesn’t get any gas.

Has anyone encountered something like this before and were you able to find the problem?

First, the simple stuff. The hard turning is normal. When the engine dies you lose your power steering.

Second, the only AC component that could possibly conk the engine would be the compressor, if it bound up tightly. If that did happen, it more likely would pop the fanbelt. If it did not, it would stay bound up. In short, the problem is not AC related.

All vehicles since 1996 have been required to have OBDII (onboard diagnostic) systems that store fault codes. Try having your computer scanned for fault codes at tha local parts store. Many of them will do this for free. Post the codes here.

Oh, and once the engine shuts down, the AC compressor stops conpressing refridgerant, so even if it still feels like the AC is running, it isn’t. The “electrical”, meaning I assume the lights, dash, etc., will keep working as ling as there’s battery power left.

"I tried to restart the vehicle and it wouldn't crank over."

Do you mean to say that the starter wouldn’t even make noise, trying to start the car or do you mean that the car’s starter is making its normal noises but it isn’t starting.
IF you meant to say that the starter isn’t making noises, I’d check the battery connections. Also check the connections where they are going.

A running car abruptly stopping could be a lot of things. I’m assuming you are certain the gas tank is not empty. Usually a problem like this is fairly easy to diagnose. Like @thesamemountainbike said, the first thing to do is get the codes and if you like, post them here. Folks here know how to interpret the codes, then they can give you some help on your particular problem.

My first impression though given the symptoms would be what you say, a fuel problem, like a faulty fuel pump or faulty fuel pump relay. It could be the prior work on the AC, they accidentally did something to change the wiring to the relay or the fuel pump.

Every time it happened, the vehicle had fuel.

The starter makes noise so its not that the starter has gone bad, its just that the car wouldn’t start up right away.

The lights, etc…all electrical was working.

They replaced a computer module that works with the ac. The compressor is fine.

I think they ran diagnostics the first time we took it in and nothing came up, but I may be wrong.

DH is calling mechanics today as yesterday, the vehicle acted as though it was going to quit and then suddenly the engine independently kicked up the RPMs. It didn’t stall but he thought it was going to and I’m wondering if this is telling in any way.

Thanks for the input and I’ll keep y’all posted when I have something more to share.

Because the vehicle had fuel does not necessarily mean it was getting pumped to the throttle body with the necessary pressure. George’s suggestions are directed toward the fuel’s delivery. This can be tested with a simple fuel pressure test kit, basically a fitting and a pressure gage.

It’s good to hear that the starter is (if I understand your correctly) turning the crankshaft. That eliminates one subsystem.

it’s also good to hear the lights etc. were working. that does eliminate some possibilities. Be aware, however, that it takes much more electrical power to start the engine than to just operate lights. One cannot infer from the lights operating that the battery has sufficient power to start the engine. As with the fuel pump, the battery and charging system are easy to test…and their connections. Both should be checked out.

Diagnostic should be tried again. You may have stored a code since the first time.

This added information does help. Combined with the codes (if there are any) and the other information you’ve provided, it shoudl help him along the right path.

A fuel pump pressure test will determine if the fuel pump is weak or the filter is clogged, but it won’t diagnose a fuel pump relay problem. If the truck runs good when its running, then the pump and filter are probably good.

Even though you have electrical, that does not mean you have ignition (spark). The problem with an intermittent problem is that you can’t troubleshoot it if everything is working. You can only trace the problem when the truck is not running. Your plan to leave it with the mechanic is a good one. If the problem occurs when they are driving it, they will quickly determine if it is spark or fuel.

Thanks for the responses. the truck is heading to the shop today and I hope they can explore these other options. I’ll keep y’all posted.