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Greg A
Greg A, Master Troubleshooter
Category: Chevy
Satisfied Customers: 8856
Experience:  Working with Electronics & Cars for 25+ Years
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My 2002 chevy Tracker 2.5l 6cyl automatic chugs when I ...

Resolved Question:

My 2002 chevy Tracker 2.5l 6cyl automatic chugs when I drive, but only after it goes about 8 miles, less sometimes. I thought it was a fuel filter, changed that, but no difference. I''ve had a SES light on for quite a while and it was Scanned and said it was an EVap code.Mechanics said I wouldn''t notice any drivability problems, and i haven''t until now. Its been 5months since that light came on. Mechancics now say that its the Mass airflow sensor, but the dealer says I don''t have one. Mechanics show me its connected to the top of the airfilter.Syptoms are worse for driving when going up hill. When I drive uphill in reverse it runs fine. Weird, I know...It also smells putrid when its ''trying'' to go. It will go into overdrive when I stomp on the pedal, which I also did out of curiosity, so I am just stumped about this. It stalls at intersections (sometimes) and sometime when I slow down turning into a parking lot or some such scene. Anyway...HELP!
Submitted: 9 years ago.
Category: Chevy
Expert:  Greg A replied 9 years ago.

HiCustomer Thank you for asking your question on Just Answer.

Did you happen to write down the EXACT error code that is turning your light on?
It should be 1 letter and 4 numbers.

I did check on the MAF, and the manual says "The mass air flow (MAF) sensor is an integral part of the throttle body assembly and cannot be serviced separately."


Customer: replied 9 years ago.
I do now...there were two actually:
P0447 and P0445..evap vent solenoid: low voltage, and evap purge solenoid; high voltage. What definative troubleshooting can be done to say that the MAF is what the problem is?
Thank you, XXXXX XXXXX
Expert:  Greg A replied 9 years ago.

Hi again.

I am not sure how the MAF became suspect, but the EVAP system will definitely cause problems if it is not functioning properly. Here are a few PDF files, that you should be able to view on your computer and print. These will describe the system and the two codes you gave me.

EVAP Description

Here is the main schematic that goes along with the error code testing procedures and a couple of diagrams that show where the main components of this system are.





What I would do is have that EVAP system checked and fixed. Again, if it is not working correctly, it could be causing the engine to not run properly, because the control systems will not be feeding the correct amount of fuel into the system at all times.

Once the EVAP system is functioning properly, the codes should be cleared and the system should perform better. Then if there are any remaining problems, they can be addressed.

I hope this helps. Please let me know if you have more questions.

Take Care, Greg A.

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