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?

 

[jopizz]

Did you do any tests on the injectors. A clogged or misfiring injector will cause the same symptoms but often does not give a code. Also a bad fuel pressure regulator will feel like a misfire at idle.

 

[ErnieR]

Bad coils on the 2005 I had wouldn't throw a code.

 

[canon]

Change the fuel filter

Did you check the coils?

 

[Randy M]

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?

Are you using ethanol gas? A number of years back my '02 started doing the same, just sporadically missing. My car sat/or was infrequently started in the garage.

I switched to non-ethanol fuel and that solved my issue. Ethanol fuel will break down after sitting in the tank for prolonged periods -- the absorbed moisture will separate out to the bottom of the tank. When this stuff gets 'sucked' into your fuel system it really creates problems. If the car is a daily driver it will consume the contents in the tank before this can occur.

 

[MontyBird]

Thanks to all and sorry for the late reply, life gets in the way of driving the Bird!
I burned the old fuel, and added a can of BKK injector cleaner with fresh gas. Some spirited driving later, it is purring along.
Sadly, we cant but non-ethanol gas in Canada, or at least not that I'm aware of, and I dont drive the Bird as much as I want to. So yes, that evil potion can cause problems ( honestly, we are growing corn to burn in cars while millions in the world are starving???)
I will certainly add a delete ethanol additive when I put it away for winter.

The heat gauge still rises more than it used to and the fan I replaced two years ago runs constantly.
Thermostat?

 

[biddle]

So yes, that evil potion can cause problems

Ethanol is not the problem, letting the car sit for weeks or months is the problem. You can use a fuel stabilizer that will delay it from absorbing water from the air, especially in humid environments. Do to put more fuel in your vehicle than you can burn in a month. I've never had an issue in my entire life with ethanol blended fuel.

Standard E10 Gasoline (10% Ethanol): Safe for 30 to 90 days. After 3 weeks, it begins absorbing moisture, increasing the risk of phase separation, especially in humid environments.

Ethanol-blended gasoline burns cleaner inside the combustion chamber than pure gasoline, primarily because ethanol is an oxygenate