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Pete
Pete, Technician
Category: Car
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Experience:  17 years automotive training and experience.
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Chevrolet Upplander Flex fuel: HiI have a Upplander that

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Hi
I have a Upplander that after changing the oil and filter and air filter started to jerk when accelerating,
runs smoothly and fine constant throttle.
get an error values ​​in my Maxidas, CMMD, A / F Ratio Equivalance
What does that mean?
Do you have any good suggestions.
greetings
Tommy
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Customer: replied 4 years ago.


still need help.


 

I would check and make sure that nothing was left unplugged especially when the air filter was replaced.If the mass air flow sensor or another sensor is unplugged or something has come loose from the intake like the air inlet tubing or a vacuum leak of some kind this can cause the fault you have described here.

If no visible problems are located and nothing was left loose or bumped loose when these components were replaced then it may be best for a shop or dealer to inject smoke into the intake with their smoke test machine to try and locate any kind of vacuum leak.If a leak is found then it needs corrected to correct this here.

I hope this info has helped,if you need anything else let me know,thanks Pete.
Customer: replied 4 years ago.

As I wrote earlier, I've checked. Already Tried: I have also used the starting gas, with the usually get an increase in RPM if ther any lekage. regards Tommy




Does this feel like an engine misfire at all when this happens like one or more cylinders are misfiring?

Does this vehicle have a mass air flow sensor on it?

Let me know,thanks Pete.
Customer: replied 4 years ago.

Yes like one or more cylinders are misfiring?


it fels as it loses power.


Get an error values ​​in my Maxidas, CMMD, A / F Ratio Equivalance
What does that mean?


Regards


Tommy

The A/F usually indicates the air fuel mixture is incorrect and this can be caused by excess air entering the engine that is unmetered by a mass air flow sensor (if equipped on this vehicle).If your vehicle has a mass air flow sensor this would usually be in line from the engine air filter box to the throttle body on the engine.Make sure this is installed and plugged in correctly as this can cause all of these issues here.

If this is o.k. or no mass air low sensor is equipped then the best thing to do from here is to have a shop or dealer do a smoke test on the intake to see if there are any vacuum leaks on the engine as this will also cause this as well and would need corrected to correct this issue here.

I hope this info has helped in some way here,thanks Pete.
Pete, Technician
Category: Car
Satisfied Customers: 28310
Experience: 17 years automotive training and experience.
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