Stumbling Upon Acceleration

G

Goguinness

:
2015 Mazda CX-5 Touring FWD
Sometimes when accelerating out of a slow rolling stop my 2015 CX-5 will fall flat like it is stalling. Let off the pedal, then pump it a couple of times, and it comes back on, a little too much. Has anybody had this, or something similar? There are 39,000 miles on it. The last service I had they recommended a fuel service. That was without me saying anything about the stumbling problem. I have always looked at this as a profit maker for the dealer rather than a necessary thing. Am I wrong? I use regular gas only from main, busy stations.

Thanks, Paul
 
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I’d put some spark plugs in and change the air filter unless you know they’ve just been done. The plugs can break down under load although they should last longer. Either way, they are worthy items towards routine maintenance.
 
Change the fuel filter? (Assuming their is a replaceable one)

In other vehicles I’ve had that exhibited this behavior, that resolved it.
 
I would clear the spark plugs by running the engine up to 4,000 rpm several times while in neutral. This the Mazda factory recommendation. I also would use a fuel system cleaner like TECHRON SYSTEM CLEANER. I also would try different gas stations. If you press the accelerator slowly the transmission will stay in a lower gear but, if you press quickly to 3/4 or so, the transmission will drop 1 or 2 gears and away you go. I doubt there is a reason to change spark plugs unless you are ~ 75,000 miles and there is no fuel filter to change because it is part of the low pressure pump in the fuel tank. Let us know how this works for you please. Ed
 
I've experienced what you described.To me it's a delay rather than an indication of stalling.First vehicle owned with "fly by wire" throttle instead of throttle cable.I just let off and hit it once without pumping.You might try a tank of higher octane, the cheap stuff can give lousy throttle response and make the car feel doggy. Personally, I wouldn't change plugs or suspect a fuel filter.If you can give it full throttle and it accelerates to red line in each gear without stumbling,then the fuel filter is passing all the fuel the engine needs.Probably too early for changing that too.You may never eliminate the "lag" that occurs under certain conditions but some good gas and "brisk" driving (like Italian Tuneup style)to clean out the "carbon" might make a noticeable difference.
 
erhayes said:
I would clear the spark plugs by running the engine up to 4,000 rpm several times while in neutral. This the Mazda factory recommendation. I also would use a fuel system cleaner like TECHRON SYSTEM CLEANER. I also would try different gas stations. If you press the accelerator slowly the transmission will stay in a lower gear but, if you press quickly to 3/4 or so, the transmission will drop 1 or 2 gears and away you go. I doubt there is a reason to change spark plugs unless you are ~ 75,000 miles and there is no fuel filter to change because it is part of the low pressure pump in the fuel tank. Let us know how this works for you please. Ed
Click to expand...

Where did this "recommendation" come from?
 
If no CEL being set kinda makes me think of something outside of that detection loop or sensor/device really on borderline for failure at this point

I suppose it could just be a maintenance item but still seems low mileage to me for plugs.
 
paris1 said:
Where did this "recommendation" come from?
Click to expand...
Idk where he read it but higher rpm and leaning is the standard way to clear up spark plugs, even in piston aircraft manuals. I'd be looking at spark plug performance first (replace/clean (higher rpm/cleaning agent)
 
We used to just jump on the highway and go as fast as we could for as long as we could!
 
erhayes said:
The rev to 4K rpm recommendation came from my 2007 Mazda manual, if I remember correctly. Ed
Click to expand...

the spark plug inspection section of the 2013 CX-5 service manual (engine section) also has this recommendation for removing carbon deposits from spark plugs (if there are any)

1 Disconnect the ignition coils from the spark plugs.
Remove the spark plugs.
(See SPARK PLUG REMOVAL/INSTALLATION [SKYACTIV-G 2.0].)
Verify that the spark plugs do not have carbon deposits.
Is there any malfunction?
Yes Perform no-load racing at 4,000 rpm for 2 min, 2 times to burn off
the carbon deposits.
Repeat this step.
No Go to the next step.
Click to expand...
 
Make sure your intake hose is on tight and not cracked. Sometimes at a slow speed, then accelerating if the intake hose is not tight it will let air in that is not metered and lean out the air/fuel mixture causing a hesitation.
 
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