I have a 2005 Mazda Tribute with 58k miles. It has run flawlessly until the past few weeks. Only when the engine is cold it is very hard to start. It used to fire up quickly when I first turned the key. Now I have to keep cranking the engine to get it to fire. It's not the battery as there is no hesitation when the engine cranks. No SES light or codes. So far I have replaced the air filter, cleaned the throttle body and cleaned the IAC valve. No luck. If I disconnect the IAC valve, the engine fires right up and idles normally. When I reconnect it, I have to crank the engine over and over. Is this a good test for a defectve IAC valve or should I be looking elswhere?

 

Something else could be the problem....Sounds like the fuel pump or possibly just a clogged fuel filter...
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