2003 misfire - no CEL and no codes.

[MontyBird]

HI, the Bird has just started to missfire quite sporadically, noticeable at idle, no CEL, and there is definitely no pattern. We scanned it with a high end scanner, no codes, and the scanner put the car through a diagnostic run up and still no codes. AS well, for 2 years my temp gauge has always been right in the middle, even on long trips on really hot days with AC, and it is now showing running a little bit hotter and then drops to halfway, regardless of AC on or off. Fan was replaced last year and caused no issues.
Other posts suggest bad gas, and I will look into that, although I always buy at the same station. I have not changed the plugs or coils. Thoughts?

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[biddle]

What are you using to read codes?

 

[Guisey]

HI, the Bird has just started to missfire quite sporadically, noticeable at idle, no CEL, and there is definitely no pattern. We scanned it with a high end scanner, no codes, and the scanner put the car through a diagnostic run up and still no codes. AS well, for 2 years my temp gauge has always been right in the middle, even on long trips on really hot days with AC, and it is now showing running a little bit hotter and then drops to halfway, regardless of AC on or off. Fan was replaced last year and caused no issues.
Other posts suggest bad gas, and I will look into that, although I always buy at the same station. I have not changed the plugs or coils. Thoughts?

 

[MontyBird]

What are you using to read codes?

Dont know the actual name, but apparently it costs about 2 grand and looks like a small laptop. It could actually run throttle up for a diagnosis. Way more detailed than any code reader I have ever had.