Best of Deals Car Reviews Repair Shops Cars A-Z Radio Show

'03 Mazda Tribute- Engine Idles very low or stalls and oil light turns on when slowing down/stopping

When I am slowing to a stop, my engine idle gets really low (like 500rpm or less) and sometime stalls. At the same time, the oil light comes on. It does this all the time, and yes I’ve had my oil changed recently and actually I just checked it the other day and it was fine (along with all other fluids).

I’ve had the mechanic take a look at this three times and every time something gets fixed but this problem remains. They now say it’s a ghost. It is not the air intake (I’ve had all of the hoses checked and a bad one replaced). It’s not the electrical (I’ve had the spark plugs and cables replaced about a year and a half ago). I’ve pretty much had everything that a car of a certain age needs done fixed/replaced in the past year or so, and I still can’t figure out what could be causing this. A recent show had a similar problem, but the gal didn’t mention the low idle/stalling. In that show they mentioned that she should have the oil pressure gauge checked or replaced, but would that cause the low idle/stalling? I don’t know what to do and I’m very reluctant to go to a dealer :frowning:

Have you had the Idel Air control (IAC) valve checked/cleaned?? My bet is on that, and if it is… time to find a new mechanic becasue that should have been item number one on the hit list.

Plus its an under $100 Part and you can do it your self (2-3 bolts if I recall correctly and one electrical plug),or.r_gc.r_pw.,cf.osb&fp=bd1b49cb0cea10af&biw=1024&bih=602

Anbd by the way, the oil light illuminating when the idle drops extremely low should not be considered abnormal. Just be sure you check the oil regularly keep the level up beyond the “fill” line, as you should anyway.

I will elaborate a little on what mountainbike said about the oil light. First, the light is not about the oil level. Its about oil pressure. So you can have the oil up to level but still have low oil pressure. Second, if the engine shuts down, the oil pressure obviously goes to zero. So if the car is stumbling & nearly stalling then the oil pressure is just dropping with it. So the oil light when the idle gets low is probably just a symptom of the low idle.

I’d also start with cleaning the IAC valve as gsragtop noted.

I will have to call and ask them if they cleaned that. I am fairly sure they would have. They said they cleaned out all of the air intake parts just to make sure when they replaced the hose (some kind of insulated one).

I do go to a pretty reliable mechanic (recommended highly by many friends, great reviews here and elsewhere).

The problem is, they keep telling me that they can’t make it do the thing I say it does. My husband drives the car and it does the same to him, so I know it’s not just me. It’s a stick and I drive it properly (put the clutch in all the way when stopped, etc). I don’t have him to take off from work and drive around with the mechanic (which was their next suggestion). And with all the things I’ve already fixed, I am running low on car-fixing funds. Like really low.

Is there anything else (besides the IAC) that could make it do this?

Like I said the IAC would have been one of my first steps, its sole purpose is to allow air into the motor at idle to keep its speed up. When it gets clogged (sometimes you can clean it and that is almost free except for a can of cleaner), other times you have to buy a new one.

Problem is that it often does not thow a code when it fails, and mechanics today can be dumb (IE the computer says its ok, therefor it must be fine), I work at a dealership and have seen this first hand. Its they way they are being taught, to trust the computer 100% and ignore your gut.

Gsrag, I wish I could disagree with that statement but I cannot. I ran into a recent graduate of an automotive technology program recently and tried to make a joke about the chemistry involved in emissions. He looked puzzled and said “they didn’t teach us that stuff”. Now I know I occasionally make some strange jokes, but this one was pretty simple. Turns out, they’d never explained to him what actually happens in the combustion chamber.

Or perhaps he skipped that class.

I agree with gsragtop. I have a 2003 Tribute that had these same symptoms. Took it to the shop and it was the IAC. It was pretty gunked up, and the mechanic said it’s pretty common in Tributes. Had it replaced, as it was too far gone for cleaning. Runs great!

So, I finally had the mechanic replace the IAC about 6 weeks ago. That wasn’t it :frowning:

The problem has only gotten worse - and it seems to be worse when I have driven on the freeway for a while (like on my commute home). So bad that I am afraid that flooring it won’t get it up to speed to shift to the next gear! I am taking it to the dealer tomorrow out of sheer desperation… sigh.

Just wanted to post in case there are any others out there that tried the IAC fix and it didn’t work for them. You’re not alone.

Oh, by the way, I couldn’t do it myself (the IAC replacement), since in the 4-cyl Tribute the engine is sideways and the IAC was way under and behind and million things. Took us forever to find it only to figure out that we could barely reach it from any angle (and I have the arms of a 6’6" dude helping me). Sigh, my car is so sad!

I am not meaning to be critical of the advice of others, which I completely appreciate! Everyone is just trying to help, I just want to put additional info out there for everyone. Thanks so much for all your help!

Is there a check engine light involved here?

Find your EGR valve. It probably looks like a little flying saucer with a small black vacuum line attached to it. It will look like the pic below but you’ll mostly be able to really see the saucer part and yours might be silvery. The next time you stop and it is stumbling, pull that little black tube off of the port on the valve and see what happens.

If that smooths out the idle then you probably need a new EVR solenoid (it opens the EGR valve with engine vacuum). This can be pretty easily verified with a vacuum gauge. At idle that line on the EGR valve should have something very close to zero inches of vacuum. (Maybe 1 - the valve should start to open at about 1.5 inHg). If pulling that line does nothing, ask your shop if they can check out the EGR valve to see if its sticking open. If you wanted to try something yourself, take a small piece of tubing of the right diameter to slide tightly over that port on the valve and pump some pressure into it. You could try just blowing into it, or use a small ball pump or something. That won’t be definitive if nothing happens, but if it cures the stumble then your EGR valve needs a good cleaning or possibly replacement.

Thanks cigroller! I will certainly mention this to the mechanic tomorrow - I am so done trying things myself, unfortunately. (too much failure!)

There is no check engine light on. If it was that, then I could probably get a computer code, but alas, no light. Just the oil pressure light flickering on at low idle and getting worse. I’m nervous about driving to the mechanic, but I’m sure I can make it a few miles…

If your mechanic says that it can’t be the EGR because it would set a code (because it should), just ask that he try it anyway. The computers aren’t as smart as people want to give them credit for, and they have a lot of tolerance for misbehavior built in.

The oil light is a result of the engine stopping. That is normal.

This additional information makes me wonder of the fuel line pressure is low (failing pump, fuel pressure regulator, plugged filter) or something inside the exhaust system has collapsed and is restricting output (cat converter core or muffler baffles would be the first suspects).

Let us know what the shop finds.

Car is still at the dealer (dropped it off Saturday!)

They replaced the fuel pump, as they claim there was no pressure. I had to buy my own and bring it to them to avoid some serious gouging.

Now they say the flywheel sheared off the crakshaft sensor (I think!) and they have my transmission apart and are looking at the flywheel. The only good news so far is that they’ve replaced the sheared off part at no cost to me.

They already checked the timing belt (which I had replaced recently, but they wouldn’t listen) and suspected the spark plugs and the ignition coil. I am getting very afraid that I’m going to get taken - but I’m no sap! I’ve made it very clear they cannot do anything that costs me my hard earned $$ without telling me (which is the way it should be anyways).

What do you guys think? Should I just take my car back? I would really like this ghost out of the machine, but not if it ends up with a gigantic bill!

So apparently there IS a ghost in the machine. The crank sensor that was sheared off was continuing to tell the computer that it was in tact and readings were A-OK. The shop has been on the phone with Madza (I imagine manufacturing or some other such people) all day still trying to figure out what keeps slicing it. Apparently the crank sensor not existing would make my car have the exact problem that it’s been having for so long, but no one thought to check it because it told every mechanic that everything was fine! Not a final solution, but I’m not crazy!

Anyways - I’ll update later with the final solution when I finally get my car back!

“Flywheel sheared off the crankshaft sensor”, wot??
Sorry but that just sounds like a collection of buzzwords. It makes little sense.

OK, car is dead. They removed the tranny to see what kept hitting the crank sensor. What really happened is the crankshaft has been loose and rolling around in the engine and tearing the back of the engine wall apart. They said the flywheel was tearing it up too and the clutch is damaged. I will go down tomorrow AM to take a look for myself, but mechanic said there’s no way anyone could have known without taking the thing apart and nothing I could have done to prevent it.

Just one of those things. Very very unfortunate things.

Thanks for all of your help and suggestions in this forum!

Take some photos and post them here.
Something sounds odd from here.