Primetime1957

I have a 2005 Ford Taurus 6 cyl. The past few months the car has had intermittant starting problems. The engine cranks over just fine but will not start up. Doesn't matter if it's hot, warm, or cold. I hooked it up to a scan tool and got the PO300 code which is interrmitant misfire code. The car has not really run bad after starting. Through the options of possibilities I replaced the coil pack and the car has started just fine the past few weeks. 2 days ago the starting problem has returned. I hooked the scan tool back up and it shows no codes. I can unhook a plug wire, ground it with a screwdriver to check for spark and the engine will fire right up. Any ideas what to check for ?

R.S.LOGAN

Could check engine coolant temp sensor (ECT) and also all earth / ground wires ..

RickMN

When you first turn the key, all the warning lights come on. Look for the Check Engine/Service Engine Soon light. Then crank the engine. IF the computer is getting good signal from the crankshaft sensor, the light will turn off. If it stays on, you've found your problem. Replace the crankshaft sensor.

If it does go off, then I'd suspect a bad coolant temp sensor. Takes less time and money to replace it than to test it.

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I'm a retired ASE Master/L-1 Technician. I still keep current with the latest automotive technology. Visit my blog for cool articles and TSB's: http://www.ricksfreeautorepairadvice.com/