THE MYSTERY MACHINE sputtering and dying at red lights!

My van (Mazda MPV 2005) has been sputtering while driving for a while. Now I am dying at redlights when trying to accelerate after I have driven longer than a quick trip. I have had 4 mechanics work on my van and all of them, in the end, shrug their shoulders and tell me that they don’t know what the problem is.

The first thing (seemed unrelated at the time) was a PCV hose replaced along with 2 coils.

A few months later the engine light came on (now it stays on) and the code reads P2179 (Fuel system too lean at off idle [left bank]) So then, the Idle Air Control Valve was replaced. I had the third mechanic replace the Air Mass Meter Boot and 2 days later the problem came back. He checked the MAF sensor which was good and he gave it back and told me he didn’t know what it could be. Lastly, I took it to a dealership and they thought it was the Lower Intake Manifold Gasket, which got replaced. They also checked the O2 sensor, it is good. Within a couple of days I noticed the problem was still there. I also had a friend who is a mechanic pull out the fuel pump and it was in working order.

To top it all off, I now hear an odd “boing boing boing” coming from underneath my van when I have driven the van for a while and park. ANY IDEAS??? Please help! I’m at my wits end!

Mazda MPV
Model-Year ?


It’s a Mazda MPV 2005

Just Throwing This Out Here. Did The Dealer Check For Improper PCM Software Or Has It Been Reprogrammed ?
Mazda’s Got A Bulletin (June/06) For Their Technicians Involving Only Some 2005 - 2006 MPVs And Drops In Engine RPM Or Stalls At Idle.

The improper software causes a lean air-fuel ratio. Mazda dealers should be able to check and or reprogram the PCM if it’s needed.

How many miles on the vehicle ? I’m guessing that you’re out of the emissions warranty period ?


90, 000 miles… and I guess the warranty is up? not sure.

I don’t think that they checked that… can’t be certain though. I will take it in and check it. Do I have to take it in to the dealer or can I take it to another mechanic?

With PCM programming, it is generally best to use the dealer shop. They, for sure, have the right equipment and programming to re-flash the memory of the PCM. The equipment is expensive, so most independents may not have it.

Great! Thank you! I will check back in once I have tried this, to let y’all know! Happy Thanks giving!

Ask someone to temporarily disable the EGR valve and isolate whatever ports it has to the exhaust and intake. See is that does anything.

(An EGR problem should set an error code, but computers are really dumb).

A vacuum leak can cause a problem like this and my opinion is that the possibility of a vacuum leak should always be weeded out as a first step for one reason. That reason is because connecting a vacuum gauge takes mere seconds and will reveal in an equal number of seconds if a vacuum problem exists or not.

The downside? Few mechanics seem to use or know how to interpret a vacuum gauge. Aircraft mechanics and pilots rely heavily on them in regards to piston engine aircraft. Just try to find a piston engine plane without a dash mounted vacuum gauge. :slight_smile: