Question about 1999 Mercury Cougar
When starting my engine it will start up and stall or idle at a low RPM around 400-500. To start i have to put foot on the gas and keep it at about 1500 rpm and easily let off gas so it wont stall, if i just let off gas it stalls until engine is warm. 2.5L V-6 with manual 5-speed transmission.
Common issue at the shop (i'm a ford technician), here is what I do to correct it.
Here is the most common cause of surges and stalls at stops and low erratic idle speed and rough idle, it is the idle speed control air-bypass valve and throttle valve (IAC for short), they get full of gunk over the miles and cause idle issues (stalls, low idle) like yours, Get a can of intake cleaner from any local parts store, not carb spray, intake cleaner, it is made by a company called CRC, remove the air intake hose to the engine, hold the idle high so the engine won't stall, then spray the can of cleaner into the intake while keeping the engine running, use at least 1/2 the can, shut down the engine and disconnect the battery for 5 minutes, then restart and complete a number of mixed driving cycles, town, freeway, stop and go etc., after a few days the problem will go away as the system will relearn to the clean intake.
Posted on Mar 11, 2009
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