Hesitation under acceleration

Call Paul

Hi All,

My '03 conv sputters and hesitates under full throttle; at first I thought it might be bad gas (very similar symptoms), but I suspect more. Ima upload my Blue Driver logs, if anyone can peak and give me an idea of where to look?


I uploaded it as a txt file, but if you change it to csv, it should open properly as it wouldn't allow me to attach it otherwise.


  • BDDataLog 1FAFP44483F305022 52321 118 PM.txt
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6 Shooter

Well-Known Member
Sorry to say that your data log and in its current format is humanly unreadable.

Columns of data needed are coolant temp, inlet air temp, STFT for bank 1 and bank 2, MAF count, RPM, engine load, Battery voltage, Spark, spark source code, desired pressure across injector (fuel pressure), fuel pump voltage from the table, fuel pressure from the pump, fuel pump duty cycle, fuel source code, idle air valve duty cycle. and absolute throttle position. These columns of data need to be loaded into an Excel spreadsheet.

At that point, each column needs to formatted into easily read decimal digits. For example, fuel pressure needs to be in whole numbers, not 40.01785 (40 with 5 decimal digits). Just 40 psi is easily read and understood. MAF counts, RPMs, spark, spark and fuel source, inlet temp and coolant temp in whole numbers as well. Battery and time need only one decimal digit. Fuel pump duty cycle and flow need 3 decimal digits. Voltages at the pump need 2 decimal digits.

The analog column is wideband O2 data. My yellow highlighting is for reference or identifying significant info or significant changes.


  • Photo Example of Data Log 5-25-2021.jpg
    Photo Example of Data Log 5-25-2021.jpg
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Well, I can't see the data log. But most of my vehicles not having OBD2...

I would start with ignition system: spark plugs, ignition timing, maybe the coil pack. Then I would look at fuel pressure, then vacuum.

Airflow issues usually result in the car feeling 'wheezy' (blocked filter, collaped catalytic converter or muffler). So if it's not doing that, and the ignition and fuel pressure is fine, then I would check the injectors.