I recently purchased a 2000 Mazda Miata LS with 133K miles at an estate auction. The car had been sitting for six months with a near-empty fuel tank. CarFax indicated one owner car with no accidents or repair work.

Upon purchase, I immediately stopped at the Exxon station, poured in a can of SeaFoam, and filled up the tank with 92 octane. The car ran fine; however, after 20 min the check engine light illuminated. I wasn’t greatly concerned as I realize high mileage engines can have minor sensor problems that pop the MIL.

I drove the car about 150 miles inside two weeks (this car was purchased as a Sunday-Go-Driving vehicle) and parked it in the garage. Two weeks later, I decided to drive the car 300 miles to visit family. 200 miles into the trip, the car shut down while cruising at 70 MPH.

I pulled over and immediately tried restarting the engine. The engine would turn over easily, but it wouldn’t fire. After letting the car sit for 20 min, I tried again. This time the engine fired and ran smoothly. Ten minutes later, while approaching a small town, the engine shut down again. There was no sputtering involved, only an immediate shutdown of the engine while all other electronics worked fine.

I called a local mechanic, and he drove over 30 min later, looked over the car, and couldn’t find an obvious problem. The car then started up fine, so I followed the mechanic to his shop. He ran codes, and two popped:

P0402 MAZDA - Exhaust Gas Recirculation Flow Excessive Detected
Possible causes
- Open or shorted CKP sensor circuit condition
- Poor CKP sensor electrical connection
- Check communication error between the ECM and TCM
- Failed CKP Sensor

P0725 MAZDA - Engine Speed Input Circuit Malfunction
Possible causes
- Open or shorted CKP sensor circuit condition
- Poor CKP sensor electrical connection
- Check communication error between the ECM and TCM
- Failed CKP Sensor

While at the mechanic’s shop, the car continued to run for 45 min at idle without any problems. He recommended I proceed on my trip since he couldn’t duplicate the problem. I drove the final 100 miles to my destination without issues.

The next morning, I purchased a fuel filter with the intent to change upon arrival back at my ranch. I began driving the 300 mile trip home, but 150 miles into the trip the engine shut down again at cruise speed. I pulled over, waited 20 min, and the engine started fine. Drove 15 miles farther, stopped at a convenience store so my girlfriend could use the bathroom. After five minutes of idling, the engine shut down again.

This was last Sunday, and all mechanics in that small town were closed. I waited 30 min, the engine started fine, and I began to drive to the next town. The engine shut down three more times en route. Each time I stopped on the side of the road, waited 10 min, and started the car again. I would only get about 5 miles, and it would shut down. (Keep in mind the engine temp, voltage, oil pressure are all normal)

Once I arrived at the next town, I got lucky and a mechanic was at his shop. He ran codes while at idle, and the same codes popped again. The car ran 45 min at idle in his shop and finally shut down. This mechanic had me start the car immediately, but it wouldn’t fire. He checked the plugs and they were getting fire while starting, so he eliminated coil/distributor as the problem. While cranking, he then shot some starter fluid into the aux fuel intake on the top of the manifold. It turned over and ran until he stopped spraying. At this point he suggested replacing the fuel filter and pump.

After doing so, the car ran all the way home without any problems; however, 10 miles before I got home the check engine light came on again.

So, here is my question. After finding your videos online, I think I should clean my MAF and EGR sensors since it’s an easy task. But if the check engine light stays on, or if the vehicle shuts down again, what do you suggest?

Also, assuming I have a fouled or faulty sensor, in your experience would that cause the engine to just shut down without a sputter or backfire?

I’m just puzzled. I hope the replacement of the filter/pump eliminates the shutdown problems. By the way, the old filter was FILTHY upon inspection. The mechanic blew through the discharge port, and out came black fluid and many particles. Is this likely because the fuel tank sat on empty for six months and my fresh tank of gas and Seafoam loosened up the gunk? Just weird since I went through three tanks of gas before the engine shut down the first time.

I would appreciate any insight you can offer. I’ve searched the Internet high and low for a similar problem that I’ve had, but I can’t find any correlation with the codes that popped and complete engine failure.
Thank you in advance for your insight, and I hope to hear from you soon.

Max Martin
___________________
Martin Ranch Management
6972 Ranch Road 2523
Del Rio TX 78840-5933
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First thing that popped in my head was fuel filter after sitting that long. I would also be worried if it was bad enough that it clogged your injectors, but you idle fine so I would go back to fuel filter.

What I find interesting is, you seem to have the problem after you heat up. I've heard of the cam sensor on 01+ being fault and failing under heat because they are in the back because of the VVT. You have an 00 like me. Your cam sensor is on the front held in my one nut and is a 5 min job to replace. I think the part was $25 from Napa when I replaced mine. That may fix your problem with code P0725 MAZDA. The EGR could just be a symptom.

If it were me and I'm cheap, I would do the fuel filter and the Cam sensor. BTW, if it has 130k mile on her and you don't know her history. I would go through the entire 60k maint schedule:

Timing Belt
Water Pump
Plugs
Wires
ALL Fluids

These cars are really easy to work on and the more you do, the more you learn. They are also pretty resilient to mistakes as my 00 can attest to. I've done more stupid stuff to and in my car then I care to admit.

 

Long shot, but easy to check: There is a green relay B5B4 in the right front relay box. With the car running, "thump" the relay with your finger. I have run across two of them that have been faulty and caused some of the type problems you are having.

 

Flying Solo & Long Shot:

Thank you for your advice! I have already replaced the fuel filter and fuel pump. Haven't had a shut down since, but the check engine light has illuminated again.

I tried the "thumping the relay" trick prior to the last shutdown, and the relay was fine.

I've had some other advice from other forums, and the cam shaft sensor seems to be the most likely culprit. I will clean or replace the EGR, Cam Sensor, Crank Sensor, and MAF this weekend.

I'll post results soon. Thank you for the help!

 

I doubt it is your crank. She is a bit more involved to replace as well.

 

I would pull the fuel pump out and inspect the inside of the tank for rust and debris. It could have caused the original pump to fail and may be detrimental to this one. You might pull the drain plug from the tank and see what comes out as well. It is on the driver's side of the tank in the lowest spot. You might find that excessive debris would eventually clog the pickup screen for the fuel pump after driving awhile and it would then fall away from it when the car is turned off.

The crank position sensor code means you should inspect and disconnect then reconnect the plug for that sensor. The sensor should be visually inspected for damage or that its mounting position may have been altered by damage or being struck. It is not likely the reason for the failure to run because I believe you would not see spark when it didn't receive a signal, and your mechanic did see a spark.

But I would start with fuel tank issues. If you find excessive corrosion, you would do well to source a cheap replacement from someone parting out a car there in Texas. We have many members in Texas between here and our sister site and I would be happy to help you find one if necessary.

Good luck.

 

Good point Six, but did he see spark only after it had set? He did say it started back up and he drove it back from the mechanic.

I do also agree with checking the gas tank, that's a great point.

 

I am trying to replace these items on my new 1999 NB 10th anniversary edition but don't know which brands are good. Any recommendations?

What do you mean by wires? O2 sensors?

 

P0402 was very common on 99-00 Miatas and can cause the CEL. Carbon buildup occurs on a very tiny hole in the top of the intake manifold. Try this, very easy, as long as you don't bend the metal gasket, and torque the bolts back down properly, it's very straightforward. It should help smooth out idle as well.

NB Intake Manifold Maintenance

 

For the timing belt, Gates, Dayco, Goodyear are all fine. The wires referred to are the spark plug wires. Pretty much any brand will do. I buy most of my replacement parts on rockauto.com. The water pump is good to change with the timing belt. Inspect the timing tensioner and idler pulleys for noise/wear by spinning them by hand. They should be smooth and not sound too dry inside, and definitely not sound or feel like they have sand in them.